Im new to DaniWeb and wanted to introduce myself.
Im interested in Web Development
Im mainly here to learn from discussions, share knowledge, and connect with other members.

Looking forward to being part of the community!

I'm curious how other developers here approach that transition. At what point do you start treating a project as production software rather than an experiment?

For example, do you prioritize observability and automated testing early, or wait until the product has proven demand? And how much architecture do you consider necessary before the first version goes live?

I've been looking at how teams such as Software Developers Pro approach this problem, and their emphasis on production engineering rather than stopping at the prototype stage got me thinking about it.

For developers who have taken projects from prototype to production, what was the biggest issue you didn't anticipate?

I've been comparing MirrorFly and Chanty recently, and I'm a bit confused about where each one fits.

Chanty seems to be a straightforward team messaging platform, whereas MirrorFly appears to offer more customization and communication APIs.

Has anyone here actually used both?

Is MirrorFly genuinely better, or is it only better if you need custom chat, voice, and video features?

Interested to hear what people like (or dislike) about each platform and which one you'd recommend.

Thanks!

github: https://github.com/golutra/golutra
Video demo: https://www.youtube.com/watch?v=KpAgetjYfoY&t=113s

With this system, you can create your own AI swarm (agent team) that collaborates automatically to:

write code

run tasks

maintain projects

manage content or social media

perform role-based workflows

produce videos, novels, and more continuously

The key is not a single AI.

It is a complete multi-agent architecture with fully customizable workflows.

What it can already do:
Multi-agent collaboration: agents divide tasks and work like a real team

Flexible workflows: adaptable to any industry or use case

Reusable CLI templates: no need to rebuild workflows from scratch

Long-running execution: agents can operate continuously like real employees

And one of the coolest parts is this:

In most desktop apps, you cant really see whats happening in the CLI. Its all hidden behind the UI.

In this system, you can click on any agent avatar and directly inspect its terminal output in real time.

Even more important for multi-agent setups:
the biggest problem is when a sub-agent goes off track or fails silently.

Here, you can talk to any individual agent at any time and adjust its behavior on the fly effectively fine-tuning the workflow while its still running.

In the future, I will develop my own CLI and agent. This is a product for the future. It's not entirely unrealistic to run it autonomously for a month . I independently developed maintained this project all by myself. So there is only one contributor.

From an SEO and usability perspective, structured headings, short paragraphs, and clear call-to-action steps improve both readability and engagement. For example, guides explaining the 8171 web portal status check process work best when the steps are broken down into simple instructions rather than large blocks of text.

Search engines also favor well-structured informational content. Clean hierarchy, proper internal linking, and optimized metadata contribute to better visibility.

In community-driven platforms, we often focus on code and backend solutions, but content clarity is equally important for user satisfaction.

https://t.me/+rx6TwJzuiZI5Mjc8

One of the biggest revelations in my journey has been understanding that users searching for calendar solutions have very different intent levels. Someone typing "calendar" into Google is likely looking for something completely different than someone searching "printable monthly calendar 2025 with holidays."

The key is identifying these intent patterns:

Informational Intent: Users looking for knowledge ("how to organize daily schedule," "benefits of time blocking," "what is a productivity system")

Navigational Intent: Users seeking specific tools ("Google Calendar alternative," "free calendar app")

Transactional Intent: Users ready to use something ("download printable calendar," "create event calendar," "free monthly planner template")

In my experience, targeting transactional and specific informational queries has generated the most valuable traffic. These users know what they want and are more likely to engage with your tool.

Here's where most productivity tools miss the mark - they chase broad, impossible-to-rank keywords like "calendar app" or "productivity tool." Instead, I've found tremendous success with long-tail variations:

• "printable calendar with large spaces for writing"
• "monthly calendar template for meal planning"
• "academic calendar with semester breaks"
• "fiscal year calendar for small business"
• "blank weekly schedule with time slots"

These longer, more specific phrases have several advantages. First, they face less competition from established brands. Second, users searching these terms have clear intent and know exactly what solution they need. Third, you can create highly targeted content that perfectly matches their needs.

The question becomes: how do you find these golden keywords? I use a combination of approaches. Google's "People Also Ask" section reveals real questions users have. Looking at autocomplete suggestions when typing calendar-related terms uncovers popular variations. Analyzing competitor content shows gaps where they haven't created resources. Forum discussions on productivity communities reveal pain points that aren't being addressed.

Creating content for a productivity tool isn't just about writing blog posts. You need to think about the entire user journey and create resources at every stage.

Template and Resource Pages: This is where productivity tools can truly shine. Create actual downloadable resources - printable calendars for different purposes, planning templates, scheduling worksheets. These pages rank well because they provide immediate value and users share them naturally.

How-To Guides: Write comprehensive tutorials that solve specific problems. Instead of generic "how to be productive," target specific scenarios like "how to schedule content creation as a solo entrepreneur" or "how to plan weekly meals with a family calendar."

Comparison Content: Users often search for comparisons when evaluating tools. Create honest, helpful comparison content that positions your tool appropriately. Don't bash competitors - instead, highlight different use cases where various tools excel.

Use Case Studies: Show how different professionals use calendar tools. "How teachers organize lesson plans," "Project manager scheduling techniques," or "How freelancers manage multiple client deadlines." These attract specific audience segments and demonstrate practical applications.

Seasonal and Timely Content: Calendar tools have natural seasonal peaks. Back-to-school planning, new year organization, tax season scheduling, holiday planning - create content that aligns with when people actively seek these solutions.

Even the best content won't rank if your technical foundation is weak. For calendar and productivity tools, several technical factors matter significantly.

Page Speed: Users expect planning tools to be fast and responsive. A slow-loading calendar defeats the purpose. Optimize images, minimize JavaScript, and ensure your site loads quickly on mobile devices.

Mobile Optimization: Most users now access productivity tools on phones. Your calendar views must work seamlessly on small screens. Test thoroughly on various devices and screen sizes.

Structured Data: Implement schema markup for your content. Event schema for calendar-related content helps search engines understand your pages better. FAQ schema for help content increases visibility in search results.

Site Architecture: Organize your content logically. Group related calendar types together, create clear navigation paths, and use internal linking to help users and search engines understand relationships between pages.

Search engines increasingly favor sites that demonstrate expertise in specific topics. For calendar and productivity tools, this means creating comprehensive coverage of related subjects.

Think beyond just calendars. Cover time management, productivity systems, scheduling strategies, work-life balance, planning methodologies, and organization techniques. This broader approach positions your site as an authority on productivity while naturally incorporating your calendar tool.

Create content clusters around main topics. For example, a cluster on "time blocking" might include: introduction to time blocking, time blocking for different professions, tools for time blocking, common mistakes, templates, and advanced techniques. Each piece links to the others, creating a robust information hub.

One underutilized strategy for productivity tools is fostering community contribution. Users who successfully implement productivity systems love sharing their approaches.

Consider featuring user stories, accepting guest posts about productivity techniques, or creating a gallery of user-customized calendar templates. This generates fresh content, provides social proof, and creates engagement that search engines value.

Discussion forums or comment sections where users share tips create naturally keyword-rich content that you didn't have to write. Moderate these spaces to ensure quality, but let organic conversations develop.

Calendar and productivity tools are inherently visual. Leverage this by creating content that showcases your tool visually.

Create infographics about productivity statistics, visual guides showing different calendar layouts, Pinterest-friendly template previews, and YouTube tutorials demonstrating features. These assets attract traffic from image and video search while providing additional entry points to your site.

While it seems counterintuitive for a digital tool, local search opportunities exist for calendar applications. Students searching for academic calendars with their university's specific dates, parents looking for school district calendars, or professionals seeking industry-specific planning tools all present targeting opportunities.

Similarly, niche-specific versions of your content can capture underserved audiences. Medical professionals, lawyers, real estate agents, and teachers all have unique scheduling needs. Content targeting these specific use cases faces less competition and attracts highly relevant users.

Building authority requires backlinks, but productivity tools must approach this carefully. The key is creating genuinely linkable resources.

Original research about productivity trends, comprehensive guides that become reference materials, free tools that complement your main offering, and beautiful templates that people want to share all naturally attract links.

Reach out to productivity bloggers, time management coaches, and organization experts. Offer to create custom calendar templates for their audiences or contribute expert insights to their content. These relationships build authentic links over time.

Finally, tracking the right metrics makes all the difference. Don't just monitor traffic volume. Pay attention to engaged sessions, feature usage, template downloads, return visits, and actual tool adoption.

Some high-traffic keywords might bring visitors who immediately bounce. Other lower-volume terms might attract users who become regular users. Prioritize content that drives meaningful engagement rather than vanity metrics.

I'm curious about others' experiences in this space. Have you found particular content types that drive exceptional results for productivity tools? What's your approach to balancing SEO optimization with genuine user value? How do you identify which features or templates to highlight in content marketing?

The productivity tools space continues evolving, and I believe there's still tremendous opportunity for well-executed organic growth strategies. What's worked - or hasn't worked - in your experience?

You can find a ready-to-run war file at https://sourceforge.net/projects/jforum2/, along with documentation.

Having worked in numerous industries, these days I freelance in various capacities, almost exclusively on web-based Java projects. I also dabble in Android on the side, but more for fun than profit.

I'm a Software Engineer, currently working as a Software Architect for a medical technology company in Belfast, Northern Ireland. We use Java, JavaScript, TypeScript, Python, we have used many of the related tooling for those languages, and our runtime environment is AWS following an "as serverless as possible" policy.

I've recently started doing some manuscript review work for Manning, for new books that they have in development, which has turned out to be quite enjoyable.

I learned of this forum only recently so thought I'd drop in and see what's going on over here.

In my day job, I work in the telecom sector, working on core network and related solutions for mostly 4G and 5G cellular networks.

I am currently spending a lot of time working with distributed microservice based solutions, often using a Java/Quarkus/GraalVM/Buildah/Podman/Linux stack.

    public class Test {
        public static void main(String[] args) {
            String text = null;
            System.out.println(text.length()); // NullPointerException here
        }
    }

How can I properly handle this scenario?

I have seen many wordpress websites doing nothing on technical seo issues but having very good page speed whereas my website is a java website and i am struggling to fix my core web vitals.

• View the list of cluster nodes, dynamically configure broker and topic settings.
• Support for consumer clients to consume messages from specified topics with group, size, and timeout parameters, displaying message details in tabular form.
• Support for PLAIN, SSL, SASL, Kerberos, sasl_plaintext, etc.
• Create (supports batch operations) and delete topics, specifying replicas and partitions.
• Statistics on each topic's total message count, committed offset, and lag for each consumer group.
• Detailed information about topic partitions (offsets), with support for adding additional partitions.
• Simulate producer behavior, send messages in batches with headers and partition specifications.
• Topic and partition health checks (completed).
• View consumer groups and individual consumers.
• Offset inspection reports.
• Support Chinese, Japanese, English, Korean, Russian and other languages

Currently supports Windows, macos, and Linux environments

HomePagegithub.com/Bronya0/Kafka-King

// File with a timestamp in the filename
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.Scanner;
import java.time.LocalDate;



// Class definition for UniqueFileNameExampleOne
public class SampleMix {
    // Main method
    public static void main(String[] args) {
                try

                (Scanner scanner = new Scanner(System.in);
                     BufferedWriter writer = new BufferedWriter(new FileWriter(generateUniqueFileName()))) 
                     {

                     while (true) {

                        System.out.print("Press Enter to enter job info or type 'exit'): ");
                        String answerdate = scanner.nextLine();

                        if (answerdate.equalsIgnoreCase("exit")) {
                            break;
                        }

                    System.out.print("Job Applied for: ");
                    String answer1 = scanner.nextLine();
                    System.out.print("Company: ");
                    String answer2 = scanner.nextLine();
                    System.out.print("Platform: ");
                    String answer3 = scanner.nextLine();

                    writer.write("Date:" + LocalDate.now());

                    writer.newLine();
                    writer.write("Job Applied For: " + answer1);
                    writer.newLine();
                    writer.write("Company: " + answer2);
                    writer.newLine();
                    writer.write("Platform: " + answer3);
                    writer.newLine();
                    writer.write(answerdate);
                    writer.newLine();
                    writer.newLine();
                    }

                //} catch (IOException e) {
                 //   System.err.println("Error writing to file: " + e.getMessage());



             //try {   
                    // Specify the directory where you want to create the file
            String directoryPath = "C:\\Users\\brett\\Documents";

            // Generate a unique file name using timestamp
            String uniqueFileName = generateUniqueFileName();

            // Combine the directory path and unique file name to get the full file path
            Path fullPath = Paths.get(directoryPath, uniqueFileName);

            // If the directory does not exist, create the directory
            if (!Files.exists(fullPath.getParent())) {
                Files.createDirectories(fullPath.getParent());
            }

            // Create the file
            Files.createFile(fullPath);

            System.out.println("File created successfully: " + fullPath);

        } 
               // Handle file creation errors
        catch (IOException e) 
        {
            e.printStackTrace();
        }

    }

          // Helper method to generate a unique file name using a timestamp
    private static String generateUniqueFileName() 
    {
        SimpleDateFormat dateFormat = new SimpleDateFormat("-yyyyMMddHHmmss");
        String timestamp = dateFormat.format(new Date());
        return "file_" + timestamp + ".txt";
    }

}

Im working on a project to develop an educational software aimed at teaching programming logic to beginners. The app will focus on short questions and mini-games to make learning engaging and interactive. Its targeted at university students in their first semesters and will primarily use Java as the teaching language.

I would love to hear your opinions or advice on:

What types of mini-games or interactive activities would be most effective for teaching programming logic?
Are there any frameworks, libraries, or tools in Java that you recommend for developing such an app?
Any tips on making the content fun and accessible while maintaining educational value?
Looking forward to your insights and suggestions.
Thank you in advance!

But the results are really weird to me , it seems between 7% and 15% of clients, depending on the app's audience, don't support WebP. In almost all of these cases, both client-side and server-side detection methods agree. It seems that the majority of them are in mobile in WebView or a similar technology.

I am writing about this because I found it extremely weird that something like this is happening but it is not reported (in my knowledge at least). I'm curious if anyone else has encountered similar issues or has real life data to confirm or refute this finding.

I have simple problem for professionalist (that i think ) but i asked all available AI about it and none was able to help and solve problem. so nothing is able to help me in this.

I have simple app that show 3 colored axes and camera that move around this scene by mouse click-hold . the problem is that after run appear first white backfround of frame for a second then its normal black background. i dont want this white at beginning.
can you tell me what in code change to get rid of this white flash at beginning ? I tried already plenty things.

This is the project code IntellJ, java , maven , with additional newest libraries lwjgl (lwjgl-release-3.31) and joml ( joml-1.10.61 ), this is whole code of 3d opengl - app 2 classes : Main and Camera , code is :

package org.example;

import org.joml.Matrix4f;
import org.lwjgl.glfw.GLFWVidMode;
import org.lwjgl.glfw.GLFWErrorCallback;
import org.lwjgl.opengl.GL;
import org.lwjgl.system.MemoryStack;

import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.util.Objects;

import static org.lwjgl.glfw.Callbacks.glfwFreeCallbacks;
import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.system.MemoryStack.stackPush;
import static org.lwjgl.system.MemoryUtil.NULL;

public class Main {

    private long window;
    private Camera camera;
    private float lastMouseX, lastMouseY;
    private boolean firstMouse = true;
    private boolean mousePressed = false;

    public void run() {
        init();
        loop();

        glfwFreeCallbacks(window);
        glfwDestroyWindow(window);

        glfwTerminate();
        Objects.requireNonNull(glfwSetErrorCallback(null)).free();
    }

    private void init() {
        GLFWErrorCallback.createPrint(System.err).set();

        if (!glfwInit()) {
            throw new IllegalStateException("Unable to initialize GLFW");
        }

        glfwDefaultWindowHints();
        glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
        glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
        // Request a double-buffered window
        glfwWindowHint(GLFW_DOUBLEBUFFER, GL_TRUE);

        window = glfwCreateWindow(800, 600, "3D Scene", NULL, NULL);
        if (window == NULL) {
            throw new RuntimeException("Failed to create the GLFW window");
        }

        glfwSetCursorPosCallback(window, (window, xpos, ypos) -> {
            if (firstMouse) {
                lastMouseX = (float) xpos;
                lastMouseY = (float) ypos;
                firstMouse = false;
            }

            if (mousePressed) {
                float dx = (float) xpos - lastMouseX;
                float dy = (float) ypos - lastMouseY;
                lastMouseX = (float) xpos;
                lastMouseY = (float) ypos;

                camera.rotate(dy * 0.1f, dx * 0.1f);
            }
        });

        glfwSetMouseButtonCallback(window, (window, button, action, mods) -> {
            if (button == GLFW_MOUSE_BUTTON_LEFT) {
                if (action == GLFW_PRESS) {
                    mousePressed = true;
                    firstMouse = true; // Reset firstMouse when the button is pressed
                } else if (action == GLFW_RELEASE) {
                    mousePressed = false;
                }
            }
        });

        glfwSetScrollCallback(window, (window, xoffset, yoffset) -> {
            camera.zoom((float) yoffset * -0.5f);
        });

        glfwSetKeyCallback(window, (window, key, scancode, action, mods) -> {
            if (key == GLFW_KEY_ESCAPE && action == GLFW_RELEASE) {
                glfwSetWindowShouldClose(window, true);
            }
        });

        try (MemoryStack stack = stackPush()) {
            IntBuffer pWidth = stack.mallocInt(1);
            IntBuffer pHeight = stack.mallocInt(1);

            glfwGetWindowSize(window, pWidth, pHeight);

            GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());

            glfwSetWindowPos(
                    window,
                    (vidmode.width() - pWidth.get(0)) / 2,
                    (vidmode.height() - pHeight.get(0)) / 2
            );
        }

        glfwMakeContextCurrent(window);
        glfwSwapInterval(1);
        glfwShowWindow(window);

        GL.createCapabilities();

        glEnable(GL_DEPTH_TEST);

        // Set the projection matrix
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        float aspectRatio = 800.0f / 600.0f;
        glFrustum(-aspectRatio, aspectRatio, -1, 1, 1, 100);

        camera = new Camera(20, 30, 45);
    }

    private void loop() {
        // Set the clear color explicitly
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

        while (!glfwWindowShouldClose(window)) {
            // Clear the color and depth buffers
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

            Matrix4f viewMatrix = camera.getViewMatrix();
            FloatBuffer fb = org.lwjgl.BufferUtils.createFloatBuffer(16);
            viewMatrix.get(fb);

            glMatrixMode(GL_MODELVIEW);
            glLoadMatrixf(fb);

            drawAxes();

            glfwSwapBuffers(window);
            glfwPollEvents();
        }
    }


    private void drawAxes() {
        glBegin(GL_LINES);

        // X axis in red
        glColor3f(1.0f, 0.0f, 0.0f);
        glVertex3f(-20.0f, 0.0f, 0.0f);
        glVertex3f(20.0f, 0.0f, 0.0f);

        // Y axis in green
        glColor3f(0.0f, 1.0f, 0.0f);
        glVertex3f(0.0f, -20.0f, 0.0f);
        glVertex3f(0.0f, 20.0f, 0.0f);

        // Z axis in yellow
        glColor3f(1.0f, 1.0f, 0.0f);
        glVertex3f(0.0f, 0.0f, -20.0f);
        glVertex3f(0.0f, 0.0f, 20.0f);

        glEnd();
    }

    public static void main(String[] args) {
        new Main().run();
    }
}

and Camera code :

package org.example;
import org.joml.Matrix4f;
import org.joml.Vector3f;

public class Camera {

private Vector3f position;
private float pitch;
private float yaw;
private float distance;

public Camera(float distance, float pitch, float yaw) {
    this.position = new Vector3f(0, 0, 0);
    this.pitch = pitch;
    this.yaw = yaw;
    this.distance = distance;
}

public Matrix4f getViewMatrix() {
    Matrix4f viewMatrix = new Matrix4f();
    viewMatrix.identity();

    // Calculate the camera position based on spherical coordinates
    float x = (float) (distance * Math.sin(Math.toRadians(pitch)) * Math.cos(Math.toRadians(yaw)));
    float y = (float) (distance * Math.cos(Math.toRadians(pitch)));
    float z = (float) (distance * Math.sin(Math.toRadians(pitch)) * Math.sin(Math.toRadians(yaw)));

    position.set(x, y, z);

    viewMatrix.lookAt(position, new Vector3f(0, 0, 0), new Vector3f(0, 1, 0));
    return viewMatrix;
}

public void rotate(float pitchDelta, float yawDelta) {
    this.pitch += pitchDelta;
    this.yaw += yawDelta;
}

public void zoom(float distanceDelta) {
    this.distance += distanceDelta;
    if (this.distance < 1.0f) {
        this.distance = 1.0f; // Prevent camera from getting too close
    }
}

public Vector3f getPosition() {
    return position;
}

public float getPitch() {
    return pitch;
}

public float getYaw() {
    return yaw;
}

public float getDistance() {
    return distance;
}


}

and pom.xml file is :

4.0.0
<groupId>org.example</groupId>
<artifactId>3dscene</artifactId>
<version>1.0-SNAPSHOT</version>

<properties>
    <maven.compiler.source>17</maven.compiler.source>
    <maven.compiler.target>17</maven.compiler.target>
</properties>

<dependencies>
    <!-- LWJGL dependencies -->
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl</artifactId>
        <version>3.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl-glfw</artifactId>
        <version>3.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl-opengl</artifactId>
        <version>3.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl-stb</artifactId>
        <version>3.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl</artifactId>
        <version>3.3.1</version>
        <classifier>natives-windows</classifier>
    </dependency>
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl-glfw</artifactId>
        <version>3.3.1</version>
        <classifier>natives-windows</classifier>
    </dependency>
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl-opengl</artifactId>
        <version>3.3.1</version>
        <classifier>natives-windows</classifier>
    </dependency>
    <dependency>
        <groupId>org.lwjgl</groupId>
        <artifactId>lwjgl-stb</artifactId>
        <version>3.3.1</version>
        <classifier>natives-windows</classifier>
    </dependency>

    <!-- JOML dependency -->
    <dependency>
        <groupId>org.joml</groupId>
        <artifactId>joml</artifactId>
        <version>1.10.5</version>
    </dependency>
</dependencies>

<repositories>
    <repository>
        <id>sonatype</id>
        <url>https://oss.sonatype.org/content/repositories/snapshots/</url>
    </repository>
</repositories>

The error is from this line of code:

home.addItem(new ModelItem(ID++, "Original Nuggets Meal", "", 90, "KFC", new ImageIcon(getClass().getResource("icon/img2.png"))));

i use the correct folder as it is in a package in the same source of the file. please help!

I fixed the null part but I can't seem to be able to add the first line in the list.

BufferedReader bf = new BufferedReader( new FileReader(importpath+"\\additional_info\\"+name+".txt"));
            //System.out.println(importpath+"\\"+name+".txt");
            String line = bf.readLine();
            listModel.removeAllElements();
            while (line != null) {
                line = bf.readLine();
                if(line == null){

                }else{
                    listModel.addElement(line);
                }
            }
            bf.close();
            System.out.println(listModel);
            clipsLineList.setModel(listModel);

I can only configure the database connection in the war project.What parameters should I pass to the jar project so that I can implement database query operations in the jar project.ask for advice!

I have an application with one JFrame and two modeless JDialogs. When I mimimize the JFrame, the dialogs are still there, not minimized.
So i need to hide them. I can hide them with WindowDeactivated event which runs one time when the JFrame is minimized but when I want to set the dialogs visible again I cannot use WindowActivated event because it's running continuously so the dialogs and JFrame start to flicker...

I need to minimize the dialogs when the JFrame is minimized and maximize them after the JFrame is maximized or has normal state again. Please help.

Thanks

 public static void main(String[] args) {
    // TODO Auto-generated method stub
    // Declaration and Initiation
    double[][] training = new double[75][4];
    double[][] testing = new double[75][4];
    double[][] target = new double[75][3];

    BufferedReader br = null;
    BufferedReader br2 = null;
    try {
        br = new BufferedReader(new FileReader("filepathhere\\training.csv"));
        br2 = new BufferedReader(new FileReader("filepathhere\\testing.csv"));

    } catch (FileNotFoundException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    String line = "";
    int row = 0, i;

    try {
        while ((line = br.readLine()) != null) {
            String[] token = line.split(",");
            for (i = 0; i < 4; i++) {
                training[row][i] = Double.parseDouble(token[i]);
            }
            if (row < 75) {
                row++;
            } else {
                break;
            }
        }
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    try {
        br.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    String line2 ="";
    int row2 = 0, j;
    try {
        while ((line2 = br2.readLine()) != null) {
            String[] token = line2.split(",");
            for (j = 0; j < 4; j++) {
                testing[row2][j] = Double.parseDouble(token[j]);
            }
            if (row2 < 75) {
                row2++;
            } else {
                break;
            }
        }
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    try {
        br2.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    // Defining desired output on each classes
    for (int k = 0; k < 25; k++) {
        target[k][0] = 1.0;
        target[k][1] = 0.0;
        target[k][2] = 0.0;
    }
    for (int k = 25; k < 50; k++) {
        target[k][0] = 0.0;
        target[k][1] = 1.0;
        target[k][2] = 0.0;
    }
    for (int k = 50; k < 75; k++) {
        target[k][0] = 0.0;
        target[k][1] = 0.0;
        target[k][2] = 1.0;
    }
    ...

Input is as follows for training.csv (https://drive.google.com/open?id=1zwdcnm_tVcPZD5N0Mt2O9DXE9tBEGVBh) and testing.csv (https://drive.google.com/open?id=1OGMAygObZVwvwGB6uQffmGX3Zie-GpIw).

For output, there will be three : base value, followed by values on first & second layer respectively. I have this one that is unsatisfactory :

Results are follows :

    1 : 1.0 00
    1 : 1.0 00
    1 : 1.0 00

    2 : 1.0 00
    2 : 1.0 00
    2 : 1.0 00

    3 : 1.0 00
    3 : 1.0 00
    3 : 1.0 00

    4 : 1.0 00
    4 : 1.0 00
    4 : 1.0 00

    5 : 1.0 00
    5 : 1.0 00
    5 : 1.0 00

    6 : 1.0 00
    6 : 1.0 00
    6 : 1.0 00
    .
    .
    .
    .


    75 : 1.0        00
    75 : 1.0        00
    75 : 1.0        00

How can I achieve target output, which will become three different values each, and shows how each neural networks differs each in terms of their output values?

Here is the core programming, including the Sigmoid and Derivative-Sigmoid part. I am convinced that something is wrong with the propagations' part:

// Forward Propagation

        int bias = 1;
        double learningrate = 0.03;

        for (int count = 1; count < 10000; count++) {
            for (int k = 0; k < 75; k++) {
                for (int l = 0; l < 3; l++) {
                    op_H1[l] = bias;
                    for (int m = 0; m < 4; m++) {
                        op_H1[l] += training[k][m] * weight_I_H1[l][m];
                        op_H1[l] = Sigmoid(op_H1[l]);
                    }
                }

                for (int l = 0; l < 3; l++) {
                    op_H2[l] = bias;
                    for (int m = 0; m < 3; m++) {
                        op_H2[l] += op_H1[l] * weight_H1_H2[l][m];
                        op_H2[l] = Sigmoid(op_H2[l]);
                    }
                }

                for (int l = 0; l < 3; l++) {
                    op_O[l] = bias;
                    for (int m = 0; m < 3; m++) {
                        op_O[l] += op_H2[l] * weight_H2_O[l][m];
                        op_O[l] = Sigmoid(op_O[l]);
                    }


            // Back Propagation

                }
                for (int l = 0; l < 3; l++) {
                    delta3[l] = (target[k][l] - op_O[l] * DSigmoid(op_O[l]));
                }
                for (int l = 0; l < 3; l++) {
                    for (int m = 0; m < 3; m++) {
                        weight_H2_O[l][m] += learningrate * op_H2[m] * delta3[l];
                    }
                }
                for (int l = 0; l < 3; l++) {
                    for (int m = 0; m < 3; m++) {
                        delta2[l] = DSigmoid(op_H2[l]) * weight_H2_O[m][l] * delta3[m];
                    }
                }
                for (int l = 0; l < 3; l++) {
                    for (int m = 0; m < 3; m++) {
                        weight_H1_H2[l][m] += learningrate * op_H1[m] * delta2[l];
                    }
                }
                for (int l = 0; l < 3; l++) {
                    for (int m = 0; m < 3; m++) {
                        delta1[l] = DSigmoid(op_H1[l]) * weight_H1_H2[m][l] * delta2[m];
                    }
                }
                for (int l = 0; l < 3; l++) {
                    for (int m = 0; m < 4; m++) {
                        weight_I_H1[l][m] += learningrate * training[l][m] * delta1[l];
                    }
                }
            }
        }

        // Results Displaying

        System.out.println("Results are follows :");
        System.out.println("");

        for (int k = 0; k < 75; k++) {
            for (int l = 0; l < 3; l++) {
                op_H1[l] = 1;
                for (int m = 0; m < 4; m++) {
                    op_H1[l] += testing[k][m] * weight_I_H1[l][m];
                    op_H1[l] = Sigmoid(op_H1[l]);
                }
            }
            for (int l = 0; l < 3; l++) {
                op_H2[l] = 1;
                for (int m = 0; m < 3; m++) {
                    op_H2[l] += op_H1[m] * weight_H1_H2[l][m];
                    op_H2[l] = Sigmoid(op_H2[l]);
                }
            }
            for (int l = 0; l < 3; l++) {
                op_O[l] = 1;
                for (int m = 0; m < 3; m++) {
                    op_O[l] += op_H2[m] * weight_H2_O[l][m];
                }
                op_O[l] = Sigmoid(op_O[l]);
                System.out.print((k + 1) + " : " + op_O[l] + "\t");
                System.out.println("00");
            }
            System.out.println("");
        }

    }

    static double Sigmoid(double output) {
        return 1 / (1 + Math.pow(Math.E, -output));
    }

    static double DSigmoid(double output) {
        return output * (1 - output);
    }
}

package tile;

import java.awt.Graphics2D;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import javax.imageio.ImageIO;

import main.GamePanel;
import main.UtilityTool;

public class TileManager {
    GamePanel gp;
    public Tile[] tile;
    public int mapTileNum[][];

    public TileManager(GamePanel gp) {

        this.gp = gp;

        tile = new Tile[42];
        mapTileNum = new int[gp.maxWorldCol][gp.maxWorldRow];

        getTileImage();
        loadMap("/maps/worldV2.txt");

    }
    public void getTileImage() {

            //Placeholder
            setup(0,"grass00", false);
            setup(1,"grass00", false);
            setup(2,"grass00", false);
            setup(3,"grass00", false);
            setup(4,"grass00", false);
            setup(5,"grass00", false);
            setup(6,"grass00", false);
            setup(7,"grass00", false);
            setup(8,"grass00", false);
            setup(9,"grass00", false); 
            setup(10,"grass00", false);
            setup(11,"grass01", false);
            setup(12,"water00", true);
            setup(13,"water01", true);
            setup(14,"water02", true);
            setup(15,"water03", true);
            setup(16,"water04", true);
            setup(17,"water05", true);
            setup(18,"water06", true);
            setup(19,"water07", true);
            setup(20,"water08", true);
            setup(21,"water09", true);
            setup(22,"water10", true);
            setup(23,"water11", true);
            setup(24,"water12", true);
            setup(25,"water13", true);
            setup(26,"road00", false);
            setup(27,"road01", false);
            setup(28,"road02", false);
            setup(29,"road03", false);
            setup(31,"road04", false);
            setup(32,"road05", false);
            setup(33,"road06", false);
            setup(34,"road07", false);
            setup(35,"road08", false);
            setup(36,"road09", false);
            setup(37,"road10", false);
            setup(38,"road11", false);
            setup(39,"road12", false);
            setup(40,"wall", true);
            setup(41,"tree", true);


    }
    public void setup( int index, String imageName, boolean collision) {

        UtilityTool uTool = new UtilityTool();

        try {
            tile[index] = new Tile();
            tile[index].image = ImageIO.read(getClass().getResourceAsStream("/tiles/" + imageName + ".png"));
            tile[index].image = uTool.scaleImage(tile[index].image, gp.tileSize, gp.tileSize);
            tile[index].collision = collision;
        }catch (IOException e){
            e.printStackTrace();
        }
    }
    public void loadMap(String filepath) {
        try {
            InputStream is = getClass().getResourceAsStream(filepath);
            BufferedReader br = new BufferedReader (new InputStreamReader(is));

            int col = 0;
            int row = 0;

            while (col <gp.maxWorldCol && row < gp.maxWorldRow) {
                String line = br.readLine();

                while (col < gp.maxWorldCol) {
                    String numbers[] = line.split(" ");

                    int num = Integer.parseInt(numbers[col]);

                    mapTileNum[col][row] = num;
                    col ++;
                }
                if (col == gp.maxWorldCol) {
                    col = 0;
                    row++;
                }
            }
            br.close();
        } catch (Exception e) {

        }
    }

    public void draw(Graphics2D g2) {

        int worldcol = 0;
        int worldrow = 0;


        while(worldcol < gp.maxWorldCol && worldrow < gp.maxWorldRow) {

            int tileNum = mapTileNum[worldcol][worldrow];

            int worldX = worldcol * gp.tileSize;
            int worldY = worldrow * gp.tileSize;
            int screenX = worldX - gp.player.worldX + gp.player.screenX;
            int screenY = worldY - gp.player.worldY + gp.player.screenY;
            if (worldX + gp.tileSize > gp.player.worldX - gp.player.screenX &&
                worldX - gp.tileSize < gp.player.worldX + gp.player.screenX &&
                worldY + gp.tileSize > gp.player.worldY -gp.player.screenY &&
                worldY - gp.tileSize < gp.player.worldY + gp.player.screenY) {
                g2.drawImage(tile[tileNum].image, screenX, screenY, null);
            }

            worldcol++;

            if(worldcol == gp.maxWorldCol) {
                worldcol =0;
                worldrow ++;

            }
        }

    }
}





public void paintComponent(Graphics g) {
        super.paintComponent(g);

        Graphics2D g2 = (Graphics2D)g;

        tileM.draw(g2);

        for(int i = 0; i < obj.length; i++){
            if(obj[i] != null) {
                obj[i].draw(g2, this);
            }
        }

        player.draw(g2);

        g2.dispose();
    }

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: Cannot read field "image" because "this.tile[tileNum]" is null
at tile.TileManager.draw(TileManager.java:138)
at main.GamePanel.paintComponent(GamePanel.java:109)

The Calculation class should have the following methods.
int SumOfSeries(int start, int end, int incr)
int SumOfArray(int data[], int size)
int ProductOfSeries(int start, int end, int incr)
int ProductOfArray(int data[], int size)
e.g. SumOfSeries(10,20,2) should produce the answer 90
Hint : 10+12+14+16+18+20
Similary ProductOfSeries(100,200,50) should produce 3,000,000
Hint : 100x150x200 = 3,000,000
The Menu class should have the following methods.
void displayMainMenu()
void displayConversionSubMenu()
void displayCalculationSubMenu()
void displayConversionLengthSubmenu()
void displayConversionWeightSubmenu()
void displayConversionTemperatureSubmenu()

The menu class methods should display the options available under each selected menu.
e.g. The displayConversionSubMenu() method should display the following.
Conversion Sub Menu

1. Sum of Series
2. Sum of Array
3. Product of Series
4. Product of Array
5. Exit
   If the user selects the sum of array option (option 2), your program should input the size of the array, get
   values to the array from the keyboard, create a Calculation type object and invoke the SumOfArray()
   method to calculate the sum of the Array element and to display it. After displaying the answer the same
   sub menu should be displayed. When the user selects Exit (option 0), you should exit from that sub menu.

java.lang.ClassNotFoundException:org.apache.derby.jdbc.EmbeddedDriver

The interesting fact is that When I run this application on my MacBigSur(Which I have installed on Virtual Box) then the application runs perfectly. But when I run the application on Physical Mac BigSur, then it gives the above mentioned exception.
I am pasting the code Iused for Creating connection to Database.

String dbdriver = "org.apache.derby.jdbc.EmbeddedDriver";
Class.forName(dbdriver).newInstance();
con = DriverManager.getConnection("jdbc:derby:/users/daniyalumar/4DSOFTECHDB; create = true");

FOLLOWING INPUT:

                            FOR REMARKS:

-FULLNAME -75 UPTO 100(PASSED)
-SECTION -74 DOWN TO 65(FAILED)
-SUBJECT DESCRIPTION -OTHER GRADES(INVALID GRADE EX.105)
-SUBJECT CODE
-1ST MONTHLY EXAM
-1ST PRELIM EXAM
-2ND PRELIM EXAM
-MIDTERM
-PRE-FINALS
-FINALS

#include<cstdio>
#include<cstdlib>
#include<iostream>
using namespace std;
int main(int nNumberofArgs, char* pszArgs[])

    //variables
    string var, var1;
    float cm, mile, kilometer, inch, meter, AU, fahrenheit, celsius, foot, quit, i;
    //program
    i = 1;
    while (i <= 1000000000) 
        cout << "Enter the starting unit. For a list of all units and commands, type list. To exit, type quit. Please note that this program will only loop one billion times." << endl <<endl;
        cin >> var;
        cout << endl;

            if (var == "quit")

                    return 0;

            //list of functions
            if  (var == "list")

                cout << "For cm to inch type centimeter. For inch to cm type inch. For miles to km type mile. For km to miles type kilometer. For meters to AU or feet type meter. For AU to meters type AU. For feet to meters type feet. For fahrenheit to celsius type fahrenheit. For Celsius to Fahrenheit type celsius then rerun the program." << endl << endl << endl;

            //inches to centimeters
            if  (var == "inch")

                cout << "Please enter the number of inches" << endl;
               cin >> inch;
                cm = inch * 2.54;
                cout << "Distance in centimeters:" << endl;
                cout << cm << endl;

            //centimeters to inches
            if  (var == "centimeter")

                cout << "Please enter the number of centimeters" << endl;
                cin >> cm;
                inch = cm / 2.54;
                cout << "Distance in inches:" << endl;
                cout << inch << endl;

            //miles to kilometers
            if  (var == "mile")

                cout << "Please enter the number of miles" << endl;
               cin >> mile;
                kilometer = mile * 1.609344;
                cout << "Distance in kilometers:" << endl;
                cout << kilometer << endl;

            //kilometers to miles
            if  (var == "kilometer")

                cout << "Please enter the number of kilometers" << endl;
                cin >> kilometer;
                mile = kilometer / 1.609344;
                cout << "Distance in miles:" << endl;
                cout << mile << endl;

            //meters to AU or feet
            if  (var == "meter")

                cout << "Please select which unit you would like to convert meters to out of Astronomical units and feet" << endl;
                cin >> var1;
                //AU
                if  (var1 == "AU");

                    cout << "Please enter number of meters" << endl;
                   cin >> meter;
                    AU = meter / 149598000000;
                    cout << "Distance in AU:" << endl;
                    cout << AU << endl;

                //feet
                if  (var1 == "feet")

                    cout << "Please enter number of meters" << endl;
                    cin >> meter;
                    foot = meter * 3.2808399;
                    cout << "Distance in feet:" << endl;
                    cout << foot << endl;

            //AU to meters
            if  (var == "AU")

                cout << "Please enter number of AU" << endl;
                cin >> AU;
                meter = AU * 149598000000;
                cout << "Distance in meters:" << endl;
                cout << meter << endl;

            //feet to meters
            if  (var == "feet")

                cout << "Please enter number of feet" << endl;
                cin >> foot;
                meter = foot / 3.2808399;
                cout << "Distance in meters:" << endl;
                cout << meter << endl;

            //fahrenheit to celsius
            if  (var == "fahrenheit")

                cout << "Please enter temperature in Fahrenheit." << endl;
                cin >> fahrenheit;
                celsius = (fahrenheit - 32) * (5 / 9);
                cout << "Temperature in celsius:" << endl;
                cout << celsius << endl;

            //celsius to fahrenheit
            if  (var == "celsius")

                cout << "Please enter temperature in Celsius." << endl;
                cin >> celsius;
                fahrenheit = (celsius * (9 / 5)) + 32;
                cout << "Temperature in Fahrenheit:" << endl;
                cout << fahrenheit << endl;

        i++;

    system("PAUSE");

The JAXB class generator was used to generate a set of classes for the specified XSD schema. For polymorphic types, for example, JAXB provides the following annotation to identify the name based on the name of an XML element.

@XmlElements({
    @XmlElement(name = "Dog", type = Dog.class),
    @XmlElement(name = "Cat", type = Cat.class)
})
protected List<Animal> animal;

Can such courses be offered in Jackson? Specifically, determining the type based on the name of an XML element.

import numpy 
import random 

def cup_game():

    cashprice = [0.5, 1.0 , 2.0 , 5.0]

    n_turn = numpy.random.randint(5,11)
    n_mult = numpy.random.randint(3,6)

    cups = list(range(0,15))
    x = numpy.random.choice(cashprice, 15, p=[0.3, 0.4, 0.2, 0.1])
    x = list(x)

    turn = ["t" for i in range(n_turn)]
    mult = ["m" for i in range(n_mult)]

    perks = turn + mult
    perk_assignment = random.sample(cups, n_turn + n_mult)

    perk_list = [0 for i in cups]
    for i in perk_assignment:
        perk_list[i] = perks[perk_assignment.index(i)]

    picks = 5
    multiplier = 1
    winnings = 0 
    total_picks = 0

    while picks > 0 and len(x)> 0:
        choice = x.pop()
        p = perk_list.pop()
        #print("cup:", choice, "perk:", p)
        if p == "m":
            multiplier += 1
        elif p == "t":
            picks += 1
        winnings += choice 
        picks -= 1
        total_picks +=1
        #print("winnings:", winnings, "multiplier:", multiplier, "picks:", picks, "total picks:", total_picks)

    jackpot = 0 
    if total_picks == 10:
        jackpot = 20
    elif total_picks == 11:
        jackpot = 50
    elif total_picks == 12:
        jackpot = 100
    elif total_picks == 13:
        jackpot = 200
    elif total_picks == 14:
        jackpot = 500
    elif total_picks == 15:
        jackpot = 1000
    else:
        jackpot = 0

    winnings = (winnings * multiplier) + jackpot
    return winnings
n = 10000
total = 0 
for i in range(n):
    total += cup_game()

print(total/n)

These are what was given:

import random


suits = ['C', 'S', 'H', 'D']
val = list(range(1,14))


class Card:
    def __init__(self, suits, val):
        self.suit = suits
        self.value = val

    def show(self):
        print("{} of {}". format(self.value, self.suit))


class Deck:
    def __init__(self):
        self.cards = []
        self.build()

    def build(self):
        for s in ['C', 'S', 'H', 'D']:
            for v in list(range(1,14)):
                self.cards.append(Card(s, v))

    def show(self):
        for c in self.cards:
            c.show()

    def shuffle(self):
        for i in range(len(self.cards) - 1, 0, -1):
            r = random.randint(0, i)
            self.cards[i], self.cards[r] = self.cards[r], self.cards[i]

    def drawCard(self):
        if len(self.cards) > 0:
            return self.cards.pop(0)
        else:
            return None

    def returnCard(self, card):
        self.cards.append(card)


# %%

def game():
    deck = Deck()
    deck.shuffle()
    matches = [False for i in range(13)]
    table = [[] for i in range(13)]

    win = 0

    while len(deck.cards) > 0 and win == 0:
        for i in range(1,14):
            if all(matches) == True:
                win = 1
                break
            else:
                if len(deck.cards) > 0:
                    if matches[i-1] == False:
                        card = deck.drawCard()
                        if card.value == i:
                            matches[i-1] = True
                            for j in table[i-1]:
                                deck.returnCard(j)
                            table[i-1].clear()
                        table[i-1].append(card)
                    else:
                        continue
    return(win)

#%%
wins = 0 
n = 100000
for i in range(n):
    wins += game()

winrate = wins/n
print(winrate)

In the last tutorial, we learned how to set up our own RabbitMQ exchanges and queues. In this tutorial, we will learn how to send messages to our custom daniweb-exchange.

Goals

At the end of the tutorial, you would have learned:

1. How to send messages in RabbitMQ.

Tools Required

1. A RabbitMQ server with the same custom exchange and queue from this tutorial.

Prerequisite Knowledge

1. RabbitMQ Exchanges and Queues.
2. Basic Java (only second part).

Project Setup

To follow along with the tutorial, perform the steps below:

1. Log into RabbitMQs management interface.

Send Message Using The Management Interface

The most convenient method to send a message is via the management interface itself. Keep in mind that this is only possible to users who have permission to access the management interface.

To send a message to the daniweb-exchange, follow the steps below.

1. Go to Exchanges, and then select daniweb-exchange.
   

2. Scroll down until you see Publish Message. Fill in the information exactly like the screenshot below. The Routing key and the Properties must be valid. Payload and Headers can be set with your value of choice.
   

3. Hit Publish message.

Because we used the routing key daniweb-to-my-queue, the message is automatically sent to my-queue. If we switched back to the my-queue view, then we can see the message that we just sent in the ready status.

This message will stay in the queue until it is consumed and acked.

Creating A New User

The admin user that we have been using is fine for tasks that can be done on the management interface, but for sending or receiving messages from outside the management interface, it is probably better to create a different user. To create a new user, follow the steps below.

1. Select the Admin tab.
2. On the right-hand-side navigation bar, select Users.
3. Expand Add a user.
4. Set the username to sender.
5. Sett the password to password.
6. Hit Add user.

After the user sender is created, the management interface will show that this user has no access to any virtual host.

In RabbitMQ, virtual hosts are used to isolate exchanges, queues, authorization (authentication is still shared among all virtual hosts) and many more properties. This feature is useful when you are running a multi-tenant setup.

For example, if you own a paid weather data streaming service and charges your clients to access this data, then it probably makes more sense to have two different clients, Weather Channel and AccuWeather, on different virtual hosts, so each client can have their own queues and exchanges.

Because our project system is simple, we are only going to be concerned about the default virtual host slash (/). In order to send messages, then the sender user would need the write permission to a virtual host /.

1. Click on the Name sender to go into its configuration.
2. Leave Configure regex and Read regex blank.
3. The Write regex needs to have .* as the value.
4. Finally, hit Set permission.

We can now see that the use has permission to send messages to the virtual host /.

Send Message In Code

A more normal method of sending messages with a program. Follow the steps below to create a small Java program.

1. Create a new text file called PublishSample.java under the ~/Downloads directory for your system.

2. Copy and paste the code below into the file.

    import com.rabbitmq.client.AMQP;
    import com.rabbitmq.client.ConnectionFactory;
   
    import java.io.IOException;
    import java.nio.charset.StandardCharsets;
    import java.util.concurrent.TimeoutException;
   
    public class PublishSample {
       private static final String USERNAME = "sender";
       private static final String PASSWORD = "password";
       private static final String ROUTING_KEY = "daniweb-to-my-queue";
       private static final String EXCHANGE_NAME = "daniweb-exchange";
       private static final String BODY = "Hello World From Java!";
   
       public static void main(String... args){
           var factory = new ConnectionFactory();
           factory.setUsername(USERNAME);
           factory.setPassword(PASSWORD);
           factory.setHost(ConnectionFactory.DEFAULT_HOST);
           factory.setVirtualHost(ConnectionFactory.DEFAULT_VHOST);
           factory.setPort(ConnectionFactory.DEFAULT_AMQP_PORT);
   
           try(var conn = factory.newConnection();
               var channel = conn.createChannel()){
               var props = new AMQP.BasicProperties.Builder()
                       .deliveryMode(1)
                       .build();
               channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY, props, BODY.getBytes(StandardCharsets.UTF_8));
           } catch (IOException | TimeoutException e) {
               throw new RuntimeException(e);
           }
       }
    }

3. Download the amqp-client-5.15.0.jar from https://www.rabbitmq.com/java-client.html.

4. Download the slf4j-simple-2.0.0.jar from https://repo1.maven.org/maven2/org/slf4j/slf4j-simple/2.0.0/.

5. Download the slf4j-api-2.0.0.jar from https://repo1.maven.org/maven2/org/slf4j/slf4j-api/2.0.0/.

6. Place all three jars under the ~/Downloads directory in your system.

7. In your terminal, execute the program using the command java -cp "Downloads/*" Downloads/PublishSample.java. You might need to modify the directories in the command, depending on your current working directory or operating system.

After the command is executed, then you can see another message in the RabbitMQ management system (two messages in total).

Summary

You have learned how to send messages using two different ways in RabbitMQ, as well as how to create a new user. In the next tutorial, we will learn how to consume these messages.

This is what I had so far:
Rectangle.java

public class Rectangle {

  private double length;
  private double width;

  public void getLength(){
    return length;
  }

  public void getWidth(){
    return width;
  }

  public void setLength(double newLength){
    this.length = newLength;
  }

  public void setWidth(double newWidth){
    this.width = newWidth;
  }

  public Rectangle(double length, double width){
    this.length = length;
    this.width = width;
  }


  public Rectangle(){
    length = 0;
    width = 0;
  }

  double area = length * width;

  public double computeArea(){
    return area;
  }
}

TestRectangle.java

public class TestRectangle{
  public static void main(String[] arg){

    Rectangle rect1 = new Rectangle();

    rect1.setLength = 4.0;
    rect1.setWidth = 5.0;

    System.out.println("Length: " + rect1.getLength());
  }
}

When working with Selenium, you might have run into a situation where you have to wait for long-running tasks to complete before you can interact with elements. Fortunately, Selenium has support for such situations via its many waits API.

In this tutorial, we will learn how to wait for the web page with Selenium.

Goals

At the end of the tutorial, you would have learned:

1. How to wait for long-running tasks with Selenium.

Tools Required

1. A Java IDE such as IntelliJ IDEA version 2022.2 (Community Edition).

Prerequisite Knowledge

1. Basic Java.
2. Basic Selenium.
3. Basic Spring.

Project Setup

To follow along with the tutorial, perform the steps below:

1. Clone this repository, switching to the waits branch.

Explicit Wait

First, let us get started with learning about Explicit Waits. The word explicit here refers to the element that you are waiting on, and not about the waiting time. Whether you are using explicit wait or implicit wait, you must specify a timer.

In our project, the end point /waits would take up to 5 seconds to load the words Hello World!. What do you think will happen to the test below when run?

@Test
void explicitWait(){
 driver.get("http://localhost:" + port + "/waits");

 new WebDriverWait(driver, Duration.ofSeconds(4))
       .until(_d -> driver.findElement(By.cssSelector("p")));
}

Well, because we have only waited for four seconds, it obviously would fail with a TimeOutException because the timer has elapsed before the <p> is added to the page.

org.openqa.selenium.TimeoutException: Expected condition failed: waiting for com.daniweb.selenium.SeleniumApplicationTests$$Lambda$1358/0x00000008007e7c18@fd0e118 (tried for 4 second(s) with 500 milliseconds interval)

For the test to work properly, we can simply wait for 6 seconds instead, so that the <p> element would have loaded already.

@Test
void explicitWait(){
 driver.get("http://localhost:" + port + "/waits");

 new WebDriverWait(driver, Duration.ofSeconds(6))
       .until(_d -> driver.findElement(By.cssSelector("p")));
}

The explicit condition inside until() is what makes this wait an explicit wait.

Implicit Wait

Similarly to an explicit wait, an implicit wait would also have to specify a timeout amount. There are two main differences between an explicit and an implicit wait:

1. An implicit wait is set using a different API, driver().manage().implicitWait(), instead of the WebDriverWait class.
2. Once you set an implicit wait, it is valid for the life of the session.
3. You do not have to specify an element for implicit waits. The wait simply applies to all elements that you try to find.

Here is a sample test that uses implicit wait.

@Test
void implicitWait(){
  driver.get("http://localhost:" + port + "/waits");
  driver.manage().timeouts().implicitlyWait(Duration.ofSeconds(6));

  var p = driver.findElement(By.cssSelector("p"));
}

Implicit wait can be particularly useful when you do not want to repeatedly type out explicit waits that have the same duration. For example, the explicit wait test below waits for three different elements with the same duration of 5 seconds.

@Test
void repeatedExplicitWaits(){
  driver.get("http://localhost:" + port + "/waits");

  new WebDriverWait(driver, Duration.ofSeconds(5))
        .until(_d -> driver.findElement(By.cssSelector("p")));

  new WebDriverWait(driver, Duration.ofSeconds(5))
        .until(_d -> driver.findElement(By.cssSelector("a")));

  new WebDriverWait(driver, Duration.ofSeconds(5))
        .until(_d -> driver.findElement(By.cssSelector("h1")));
}

We could save a couple of lines and use implicit waits, like below.

@Test
void shortImplicitWait(){
  driver.get("http://localhost:" + port + "/waits");
  driver.manage().timeouts().implicitlyWait(Duration.ofSeconds(5));

  var p = driver.findElement(By.cssSelector("p"));
  var a = driver.findElement(By.cssSelector("a"));
  var h1 = driver.findElement(By.cssSelector("h1"));
}

Summary

We have learned how to use implicit and explicit waits in Selenium. The full project code can be found at https://github.com/dmitrilc/Daniweb_Selenium/tree/waits.

Welcome to part 2 of the Selenium scrolling tutorial. Please follow the directions in part 1 to set up your project.

In part 1, we learned how to let Selenium decide how it wants to scroll to elements. In this part 2, we will learn about a couple more scrolling use cases, which includes scrolling by the amount of pixels.

Scrolling Along The Y Axis

In Selenium scripts, a common use case is scrolling by an amount of pixels vertically. To do this, you can use the method scrollByAmount() by the Actions API. For example, if you want to scroll down by 10 pixels and then 500 pixels, then you can use the code below.

@Test
void scrollByDown() throws InterruptedException {
  driver.get("http://localhost:" + port + "/start");

  new Actions(driver)
        .scrollByAmount(0, 10)
        .perform();

  new Actions(driver)
        .scrollByAmount(0, 500)
        .perform();

  Thread.sleep(5000);
}

The example shows how to scroll down, but if you want to scroll up, simply use a negative y delta instead. The test below initially scrolls all the way to the end, and then all the way back up.

@Test
void scrollByUp() throws InterruptedException {
  driver.get("http://localhost:" + port + "/start");

  // Scrolls to end of page
  new Actions(driver)
        .sendKeys(Keys.END)
        .perform();

  Thread.sleep(2000);

  new Actions(driver)
        .scrollByAmount(0, -1000)
        .perform();

  Thread.sleep(5000);
}

Scrolling Along The X Axis

Similarly, if you want to scroll horizontally, you can simply do that by changing the x delta to another value besides 0. The example below shows how scrolling along the X axis looks like.

@Test
void scrollByXDown() throws InterruptedException {
  driver.get("http://localhost:" + port + "/start");

  new Actions(driver)
        .scrollByAmount(100, 0)
        .perform();

  Thread.sleep(1000);

  new Actions(driver)
        .scrollByAmount(100, 0)
        .perform();

  Thread.sleep(5000);
}

Scrolling With Keyboard

Some users with certain physical disabilities might not be able to use the mouse for scrolling. So it might be beneficial to test whether the browser scrolls correctly using the commands sent by the keyboard. One way to achieve this is by sending virtual keys with Selenium.

To send keys to the browser, you can use the Actions APIs sendKeys() method, passing in one of the enums in this list.

Below are some examples of Selenium tests sending scrolling keys to the browser.

1. Page Down Key:

    @Test
    void scrollByPgDnKey() throws InterruptedException {
      driver.get("http://localhost:" + port + "/start");
   
      new Actions(driver)
            .sendKeys(Keys.PAGE_DOWN)
            .perform();
   
      Thread.sleep(1000);
    }

2. Page Up Key.

    @Test
    void scrollByPgUpKey() throws InterruptedException {
      driver.get("http://localhost:" + port + "/start");
   
      // Scrolls to end of page
      new Actions(driver)
            .sendKeys(Keys.END)
            .perform();
   
      Thread.sleep(1000);
   
      new Actions(driver)
            .sendKeys(Keys.PAGE_UP)
            .perform();;
   
      Thread.sleep(1000);
    }

3. Arrow Down Key.

    @Test
    void scrollByArrowDnKey() throws InterruptedException {
      driver.get("http://localhost:" + port + "/start");
   
      new Actions(driver)
            .sendKeys(Keys.ARROW_DOWN);
   
      Thread.sleep(1000);
   
      new Actions(driver)
            .sendKeys(Keys.ARROW_DOWN);
   
      Thread.sleep(1000);
    }

4. Arrow Up Key.

    @Test
    void scrollByArrowUpKey() throws InterruptedException {
      driver.get("http://localhost:" + port + "/start");
   
      // Scrolls to end of page
      new Actions(driver)
            .sendKeys(Keys.END)
            .perform();
   
      new Actions(driver)
            .sendKeys(Keys.ARROW_UP);
   
      Thread.sleep(1000);
   
      new Actions(driver)
            .sendKeys(Keys.ARROW_UP);
   
      Thread.sleep(1000);
    }

Summary

We have learned a couple of different ways to perform scrolling automation on the browser. The full project code can be found at https://github.com/dmitrilc/Daniweb_Selenium/tree/scrolling.

Please ignore my use of Thread.sleep() in the tutorial. I only use it to see what Selenium is doing because it runs really fast.

In the last Selenium tutorial, we learned how to perform basic actions such as clicking and sending keystrokes. In this tutorial, we will learn how to do another action, which is the scrolling action.

Goals

At the end of the tutorial, you would have learned:

1. How to perform scroll actions in Selenium

Tools Required

1. A Java IDE such as IntelliJ IDEA version 2022.2.1 (Community Edition).

Prerequisite Knowledge

1. Basic Selenium.
2. Selenium IDE.
3. Basic Spring.
4. Selenium Interactions.

Project Setup

To follow along with the tutorial, perform the steps below:

1. Clone this repository, switching to the scrolling branch.

Selenium Cannot Interact With Elements Outside The Viewport

Because Selenium follows the WebDriver specs, it cannot interact with elements that are outside the viewport. The WebDriver specification states,

If the element is outside the viewport, an element not interactable error is returned.

If you want to interact with elements outside the viewport, then you should instruct Selenium to scroll the page until those elements are visible. We will learn how to do this next.

Let Selenium Decides How To Scroll To Elements

Even though Selenium cannot interact with elements outside the viewport, it can obviously still see all the element in the DOM tree. If an element is not interactable, and Selenium can see it in the DOM, then Selenium will attempt to scroll until the element is in the viewport. The beauty of this is that you do not have to tell Selenium which direction to scroll to.

1. In the screenshot below, the link Last Link is all the way at the bottom of the viewport.
   

2. To have Selenium scroll down and then click on the Final resource link, you can use the code below.

    @Test
    void automaticScrollDown() {
      driver.get("http://localhost:" + port + "/start");
   
      var link = driver.findElement(By.linkText("Last Link"));
   
      //link.click(); //First way
   
      //Second way
      new WebDriverWait(driver, Duration.ofSeconds(5))
            .until(ExpectedConditions.elementToBeClickable(link))
            .click();
    }

Note that the example above shows two different ways of doing this. click() is super simple and should work in most cases. At some other times, though, you might need to wait until the content of the page is loaded after scrolling (think of lazy news feed). This is when you should have to wait.

Not only Selenium can scroll down, we can also have Selenium automatically scroll up to find the element. In the screenshot below, the First Link link is all the way at the top of the page.

The code example below is an example of how to have Selenium automatically scrolls up. Because Selenium first opens the browser at the top, we will have to make the browser scrolls to the bottom first by sending over the End key.

   @Test
  void automaticScrollUp(){
     driver.get("http://localhost:" + port + "/start");

     // Scrolls to end of page
     new Actions(driver)
           .sendKeys(Keys.END)
           //.keyDown(Keys.COMMAND) // For Mac
           //.sendKeys(Keys.DOWN)
           .perform();

     var link = driver.findElement(By.linkText("First Link"));
     link.click();

/*    new WebDriverWait(driver, Duration.ofSeconds(5))
           .until(ExpectedConditions.elementToBeClickable(link))
           .click();*/
  }

Notice that, in both examples, we did not have to tell Selenium which direction to scroll (up or down) at all. Selenium can automatically figure this out by itself.

Summary

We have learned how to perform a scrolling action using Selenium. If you want to learn more scrolling use cases, check out Part 2. The full project code can be found at https://github.com/dmitrilc/Daniweb_Selenium/tree/scrolling.

When creating a Selenium test, it is common for developers to want their scripts to take the same actions as a real human user would take. These action often includes clicking on elements or inputting text data into forms.

In this tutorial, we will learn how to perform both clicks and sending text on a web page.

Goals

At the end of the tutorial, you would have learned:

1. How to perform click and sending text actions using Selenium.

Tools Required

A Java IDE such as IntelliJ IDEA version 2022.2.1 (Community Edition).

Prerequisite Knowledge

1. Basic Selenium.
2. Selenium IDE.
3. Basic Spring.

I expect that you already know how to set up your project with Selenium and how to spy elements, so how I will not show how to do that in this tutorial.

Project Setup

To follow along with the tutorial, perform the steps below:

1. Clone this repository, switching to the element_interactions branch.

Clicking On Elements

Clicking on an element is the easiest and probably most common that your scripts need to take. Calls to findElement() from the WebDriver will often result in a WebElement (unless any Exceptions are thrown). The WebElement interface has the click() that you can call to perform the click action on the respective element.

The click() test in the SeleniumApplicationTests file demonstrates how to perform the click action.

@Test
void click(){
  driver.get("http://localhost:" + port);

  driver.findElement(By.cssSelector(".btn-outline-primary"))
        .click();
}

Verifying After Click

Oftentimes, we would like to verify whether something on the page has changed after a click action.

In our project, clicking on Get Started

will open up a new page called start.html.

Here is the code for loading the /start endpoint.

@GetMapping("/start")
public String start() {
  return "start";
}

If the click action leads the user to a new page, such as in the case of the Get Started button on our home page, you can verify the new pages title or URL via WebDrivers convenient methods getTitle() or getUrl().

@Test
void clickThenVerify(){
  driver.get("http://localhost:" + port);

  driver.findElement(By.xpath("//button[contains(.,'Get started')]"))
        .click();

  var title = driver.getTitle();
  assertEquals(title, "Get Started");
}

Input Text Using Selenium

Another common use case for Selenium is to use input some text into text boxes. In our project, the end point /checkout will load a form.

To input text, we can simply use the sendKeys() method from the WebDriver object. This will only work if the element is one that you can key in text to.

The test below send keys into the First name and Last name fields using sendKeys().

@Test
void inputText(){
  driver.get("http://localhost:" + port + "/checkout");

  // More organic if you click on
  // the text box before sending text
  driver.findElement(By.id("firstName"))
        .click();

  driver.findElement(By.id("firstName"))
        .sendKeys("Anne");
  driver.findElement(By.id("lastName"))
        .sendKeys("Chan");
}

Test Fidelity

Did you notice that we have only clicked on the First name text box and not the second? A real human user will not, theoretically, send text to the second field, Last name without focusing on it first via one of the following ways:

1. Clicking on the Last name text box.
2. Press Tab while having the focus on the First name text box.
3. Using some accessibility service.

Our test will still pass with flying colors, but because we did not replicate the same behavior as a real human user, our test now have reduced fidelity, which is often used to describe how real-worlds a test is. It is very possible that the website will show some a popup after clicking on the First name to show some important information.

Summary

We have learned how to perform click and input text actions using Selenium. The full project code can be found at https://github.com/dmitrilc/Daniweb_Selenium/tree/element_interactions.

While creating Selenium tests, you might have found that inspecting elements manually using the web browsers inspector could be tedious. Even after you have found the element, you still have to go through the pain of looking up the correct xpath syntax for this specific element.

To solve this problem, you can employ the use of a tool called the Selenium IDE. This program can run inside your Chrome, FireFox, and Edge browsers as a plugin.

Goals

At the end of the tutorial, you would have learned:

1. How to use Selenium IDE to generate test code.

Tools Required

1. One of the following web browsers: Chrome, FireFox, Edge.
2. A Java IDE such as IntelliJ IDEA version 2022.2 (Community Edition).

Prerequisite Knowledge

1. Basic Selenium.
2. Basic Spring.

Project Setup

To follow along with the tutorial, perform the steps below:

1. If you have FireFox, download the IDE as a plugin from the official extensions page.
2. If you have Chrome or Edge, install the IDE from the official web store.
3. This tutorial is a continuation of the basic Selenium tutorial, so go ahead and clone this repository, switching to the setup_maven_it branch.
4. After you are finished cloning the repo, start the server by running the SeleniumApplication class. You should see the Pricing Example home page at this point.

Start The Selenium IDE

After you have installed the Selenium IDE, it should show up on your browsers plugins section, usually at the top right. To start the Selenium IDE,

1. Click on the plugins icon.

2. Select Record a new test in a new project.
   

3. When prompted for the Project Name, use any name that you like.

4. When prompted for the Base URL, use http://localhost:8080**, and then select Start Recording.

5. You should now see a pop up that says Selenium is Recording at the bottom right of the page.
   

6. Your browser should have opened another tab, which is the IDEs user interface. This interface is for managing the steps recorded.

Record Steps

To record the steps that you take on the site, simply click on any element you want. The screenshot below shows the steps that I took on the web browser, clicking on random elements from the left to the right.

For each element that you spied, the IDE generates a few options for matching that element on the web browser.

You should put performance and flakiness into consideration when choosing one locator over another. The topic over performance is large and cannot be covered in this tutorial.

Generate Code From Recorded Steps

When you are done with the test, you can right-click on the test name and select Export.

The IDE can export more than just Java code. A few other languages are also supported.

The exported file might look like this:

public class TestTest {
 private WebDriver driver;
 private Map<String, Object> vars;
 JavascriptExecutor js;
 @Before
 public void setUp() {
   driver = new ChromeDriver();
   js = (JavascriptExecutor) driver;
   vars = new HashMap<String, Object>();
 }
 @After
 public void tearDown() {
   driver.quit();
 }
 @Test
 public void test() {
   driver.get("http://localhost:8080/");
   driver.manage().window().setSize(new Dimension(1728, 1015));
   driver.findElement(By.cssSelector("body")).click();
   driver.findElement(By.cssSelector(".fs-4")).click();
   driver.findElement(By.linkText("Features")).click();
   driver.findElement(By.linkText("Enterprise")).click();
   driver.findElement(By.linkText("Support")).click();
   driver.findElement(By.linkText("Pricing")).click();
   driver.findElement(By.cssSelector(".border-primary .w-100")).click();
   driver.findElement(By.cssSelector(".btn-outline-primary")).click();
 }
}

This is human-readable code, so all you need to do is to copy and paste the content of the test() method into your own code. You should modify the driver.get() call because our test uses a different port number.

After copying the recorded test into our project, we have the new test below.

@Test
void automatedTest(){
  driver.get("http://localhost:" + port);
  driver.manage().window().setSize(new Dimension(1728, 1015));
  driver.findElement(By.cssSelector("body")).click();
  driver.findElement(By.cssSelector(".fs-4")).click();
  driver.findElement(By.linkText("Features")).click();
  driver.findElement(By.linkText("Enterprise")).click();
  driver.findElement(By.linkText("Support")).click();
  driver.findElement(By.linkText("Pricing")).click();
  driver.findElement(By.cssSelector(".border-primary .w-100")).click();
  driver.findElement(By.cssSelector(".btn-outline-primary")).click();
}

You can switch to the ide_record branch of the repository to see this test in your project.

Summary

We have learned how to record automation steps using the Selenium IDE in this tutorial. The full project code can be found at https://github.com/dmitrilc/Daniweb_Selenium/tree/ide_record.

Selenium is one of the most popular web browser automation tools out there. There is no restriction on what you can use Selenium for. You can use it to build a GPU scalping bot (please dont) or build e2e tests for your website.

In this tutorial, we will be learning how to set up a Maven Spring project to automatically start and stop the server when selenium tests are run.

Goals

At the end of the tutorial, you would have learned:

1. How to set up your Maven Spring project for automated browser tests.

Tools Required

1. A Java IDE such as IntelliJ IDEA version 2022.2 (Community Edition).

Prerequisite Knowledge

1. Basic Java.
2. Basic Spring.

Project Setup

To follow along with the tutorial, perform the steps below:

1. Clone the project on from this repository.
2. Make sure that you switch to the setup_maven_it branch.

Project Overview

This is a very minimal Spring Boot project. It only contains three dependencies:

1. Spring Boot Starter Web.

        <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

2. Thymeleaf.

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>

3. Spring Boot Starter Test.

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>

The homepage was downloaded from Bootstrap.

We will not be doing too much testing in this tutorial, because this tutorial is mainly about setting up the project.

Selenium Library

The first thing that we will need to do in our project is to add the Selenium dependency into Mavens pom.xml file.

<dependency>
  <groupId>org.seleniumhq.selenium</groupId>
  <artifactId>selenium-java</artifactId>
  <version>4.4.0</version>
</dependency>

The Selenium library includes an interface called WebDriver. It is via this interface that we can interact with real web browsers.

Easily Load Web Browser Drivers Using WebDriverManager

To interact with the web browsers programmatically, we can use specific web drivers released by browser vendors themselves. There are a couple of ways to install drivers, but the easiest way would be to use WebDriverManager, which is a library that will automatically download the drivers for us.

Now, lets add the WebDriverManager dependency below into your pom.xml.

<dependency>
  <groupId>io.github.bonigarcia</groupId>
  <artifactId>webdrivermanager</artifactId>
  <version>5.2.3</version>
</dependency>

Configure Tests To Start The Web Server

Spring Boot comes with the ability to launch a web server when running tests. Spring Boot will automatically do this if you annotate the test with @SpringBootTest(webEnvironment = RANDOM_PORT).

Our empty test class now looks like this.

@SpringBootTest(webEnvironment = RANDOM_PORT)
class SeleniumApplicationTests {


}

We will need to know the port number of the started web server at runtime. To inject this port number, we can use the @LocalServerPort on an int instance variable.

@LocalServerPort
int port;

Write The Selenium Test

Follow the steps below to set up the Selenium test.
First, we create an instance variable for the WebDriver. This is the object that will interact with the web browsers for us.

WebDriver driver;

Next, we create a method to have the ChromeDriver downloaded and made available at runtime. Note that this also means that the driver can only interact with Chrome.

@BeforeAll
static void setupAll() {
  WebDriverManager.chromedriver().setup();
}

For each test, we need to create a new session.

@BeforeEach
void setup() {
  driver = new ChromeDriver();
}

We also need to close the session after each test.

@AfterEach
void teardown() {
  driver.quit();
}

Finally, we create the test logic. This test will wait until the browsers title matches the text.

@Test
void test() {
  driver.get("http://localhost:" + port);

  new WebDriverWait(driver, ofSeconds(5))
        .until(titleIs("Pricing example  Bootstrap v5.2"));
}

To run the test, you can simply use the run button in your IDE or use the command mvn test.

Solution Code

SeleniumApplicationTests.java

@SpringBootTest(webEnvironment = RANDOM_PORT)
class SeleniumApplicationTests {

  @LocalServerPort
  int port;

  WebDriver driver;

  @BeforeAll
  static void setupAll() {
     WebDriverManager.chromedriver().setup();
  }

  @BeforeEach
  void setup() {
     driver = new ChromeDriver();
  }

  @AfterEach
  void teardown() {
     driver.quit();
  }

  @Test
  void test() {
     driver.get("http://localhost:" + port);

     new WebDriverWait(driver, ofSeconds(5))
           .until(titleIs("Pricing example  Bootstrap v5.2"));
  }

}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
     <version>2.7.2</version>
     <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.daniweb</groupId>
  <artifactId>selenium</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>selenium</name>
  <description>A project teaching Selenium</description>
  <properties>
     <java.version>18</java.version>
  </properties>
  <dependencies>
     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
     </dependency>
     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
     </dependency>

     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
     </dependency>
     <dependency>
        <groupId>io.github.bonigarcia</groupId>
        <artifactId>webdrivermanager</artifactId>
        <version>5.2.3</version>
     </dependency>
     <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <version>4.4.0</version>
     </dependency>
  </dependencies>

  <build>
     <plugins>
        <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
     </plugins>
  </build>

</project>

Summary

We have learned how to configure Spring Boot to run automated browser tests in this tutorial. The full project code can be found at https://github.com/dmitrilc/Daniweb_Selenium/tree/setup_maven_it.

While Functional Interfaces and Function Types are used to declare the types of a function, Function Literals create the actual implementations of these types.

In this tutorial, we will learn what Kotlin Function Literals are and how to create them.

Goals

At the end of the tutorial, you would have learned:

1. How to create lambdas.
2. How to create anonymous functions.

Tools Required

1. A Kotlin IDE such as IntelliJ IDEA version 2022.2 (Community Edition).
2. The Kotlin version used in this tutorial is 1.7.10.

Prerequisite Knowledge

1. Basic Kotlin
2. Function Types

Project Setup

To follow along with the tutorial, perform the steps below:

1. Create a new Kotlin project using Gradle as the build system.
2. For the Project JDK, use JDK 18.

Lambda Expressions

The syntax for a lambda expression includes the following rules:

1. Must always be surrounded by curly braces.
2. Parameters go inside the curly braces, to the left of the arrow (->). Type annotation is optional if no explicit function type is declared on the variable, parameter, and return type.
3. The body goes inside the curly braces, after the arrow (->).
4. Unless the return type of the lambda is Unit, the lambda implicitly returns the last expression or the single value.

Here is an example of a lambda expression:

val timesTwo: (Int) -> Int = { x: Int -> x * 2 }

Because the type declaration already specified the parameter type, we can skip that in the lambdas parameter as well.

val timesThree: (Int) -> Int = { x -> x * 2 }

The type declaration can be skipped entirely when the lambda contains enough information for the compiler to infer the parameter and return type.

val timesFour = { x: Int -> x * 2}

Here is an example of lambda expression being used as function arguments.

fun onClick(listener: (Any)->Unit){}

onClick (
   { any -> }
)

And here is an example of lambda expression being used as return values

fun getLambda(): (Int)->String {
   return { x -> "$x" }
}

This is an even shorter version of getLambda().

fun getLambda() = { x: Int -> "$x" }

Passing Trailing Lambda Syntax

When the last parameter of a function is a function, then you can use a special syntax called passing trailing lambda, which allows you to place the lambda expression outside the parentheses.

The onClick() function used in the previous section

onClick (
   { any -> }
)

can be we rewritten using the passing trailing lambda syntax

onClick { any ->  }

Since the listener was the only parameter on onClick(), we can skip the parentheses entirely.

Anonymous Functions

Anonymous functions are similar to lambdas, but with only a few differences:

1. You do not need to wrap it inside curly braces.
2. It looks exactly the same as a regular function, but without a name.
3. You can use the return keyword directly in the function body.

Below is an example of an anonymous function being used with a variable.

val timesTwo = fun(x: Int): Int {
   return x * 2
}

timesTwo(1)

Here is an example of an anonymous function being used as a return value.

fun getLambda3(): (Int)->String {
   return fun(x: Int): String{
       return "$x"
   }
}

and its shorter version

fun getLambda4() = fun(x: Int): String { return "$x" }

Finally, this is how you can pass an anonymous function as an argument to another function.

onClick(fun(any){})

Summary

We have learned Kotlins lambda expressions and anonymous functions in this tutorial.

When working on real code, I rarely see anonymous function being used over lambda expressions because anonymous functions are much more verbose.

Whenever I want to express method parameters, return type or variables as a method in Java, I often find myself having to do a bit of work:

1. If I cannot remember which pre-made functional interface to use, then I will have to look up the list of pre-made functional interfaces from the Java SE documentation.
2. But the problem does not stop there. If none of the functional interfaces on the list fit my use case, then I would have to resort to making my own functional interface. This is tedious and pollute my project with functional interfaces, especially if they are only used once.

Kotlin (and a few other languages) have a feature called Function Type, which allows you to declare function parameters, function return value, and variables as having a function as their types. With function types, we can skip creating our own functional interfaces, reducing boilerplate.

In this tutorial, we will learn how to use Function Types in our code.

Goals

At the end of the tutorial, you would have learned:

1. How to create and use Function Types.

Tools Required

1. A Kotlin IDE such as IntelliJ IDEA version 2022.2 (Community Edition).
2. The Kotlin version used in this tutorial is 1.7.10.

Prerequisite Knowledge

1. Basic Kotlin.
2. Java Functional Interfaces (optional).

Project Setup

To follow along with the tutorial, perform the steps below:

1. Create a new Kotlin project using Gradle as the build system.
2. For the Project JDK, use JDK 18.

Function Type As Function Parameter

The code below illustrates how Functional Interfaces can be used on Java method parameters.

void functionalParams(Function<Integer,Integer> timesTwo){
  timesTwo.apply(1);
}

This is the Kotlin equivalence.

fun functionalParams(timesTwo: Function<Int, Int>){
   timesTwo.apply(1)
}

Using Function Type, the Kotlin equivalence can be rewritten as.

fun functionTypeParams(timesTwo: (Int)->Int){
   timesTwo(1)
}

As you can see, Function<Int,Int> has been replaced with (Int)->Int, which has the same parameter type and return type as Function<Int,Int>s SAM (single abstract method) Integer apply(Integer t).

In my opinion, (Int)->Int is easier to read than Function<Int,Int> as well because the SAM is completely exposed as you are reading the code. When encountering Javas functional interfaces, I often find myself looking up the method signature of the SAM as a sanity check.

As an added bonus, we were able to skip the apply()/invoke() function call as well because of the convenient invoke() operator.

Function Type is not an exclusive to Kotlin, other languages that I am familiar with also have a similar feature. TypeScript and Swift versions of functionTypeParams() are shown below.

TypeScript:

function functionTypeParams(timesTwo: (n: number) => number) {
timesTwo(1)
}

Swift:

func functionTypeParams(_ timesTwo: (Int)->Int) {
    timesTwo(1)
}

Function Type As Function Return Type

Function Types can also appear as a functions return type. The code below shows how this looks like.

fun returnFunctionType(): (Int)->Int = { n -> n * 2 }

Kotlin allows us to skip explicit type declaration for return types as well, so we can have the return type inferred by the compiler, producing a shorter version below.

fun returnFunctionTypeAlt() = { n: Int -> n * 2 }

Function Type As Variable Type

Lastly, you can also assign Function Types to variables.

val timesTwo: (Int)->Int = { n -> n * 2 }
timesTwo(1)

Similarly to how we were able to skip the explicit type declaration, we can also skip the explicit type declaration on variables.

val timesThree = { n: Int -> n*3 }
timesThree(1)

Higher-Order Functions

A function is also considered a Higher-Order Function when it either receives a function as a parameter or returning a function.

1. Create an array of item names. Use the following item names: Bread, Milk, Butter, Chips,
   Honey, Soap, Towel, Carrots, Beans, Samp, Dress, Pants, Shoes, Socks.
2. Create an array of item prices. Use the following item prices: 15.50, 12.00, 56.00, 20.00, 45.00,
   7.00, 75.00, 8.00, 5.00, 12.00, 200.00, 150.00, 400.00, 25.00.
3. Display every item name and its corresponding price. See the sample output given.
4. Print the average price of all the items.
5. Find and display the price of a specific item
   a. Read in the name of the item.
   b. Loop through the items array and look for the specific item.
   c. If the item is found, display the price of the item.
   SAMPLE OUTPUT
   Display every item name and its corresponding price.
   Items in stock with prices

   Bread - R15.5
   Milk - R12.0
   Butter - R56.0
   Chips - R20.0
   Honey - R45.0
   Soap - R7.0
   Towel - R75.0
   Carrots - R8.0
   Beans - R5.0
   Samp - R12.0
   Dress - R200.0
   Pants - R150.0
   Shoes - R400.0
   Socks - R25.0
   Display the average price of all the items
   The average price of all the items is R73.6
   Find and display the price of a specific item Sample input and output
   Sample run 1 Sample run 2
   Item Look-up
   What item are you looking for?
   Dress
   The price of item Dress is R200.0
   Item Look-up
   What item are you looking for?
   hjgjg
   Item hjgjg is not stocked in the shop.

What I have:

public class ShopApp


public static void main(String args[])


Shop items[]=new Shop[14];
items[0]=new Shop("Bread", (int) 15.00);
items[1]=new Shop("Milk", (int) 12.00);
items[2]=new Shop("Butter", (int) 56.00);
items[4]=new Shop("Chips", (int) 20.00);
items[5]=new Shop("Honey", (int) 45.00);
items[6]=new Shop("Soap", (int) 7.00);
items[7]=new Shop("Towel", (int) 75.00);
items[8]=new Shop("Carrots", (int) 8.00);
items[9]=new Shop("Beans", (int) 5.00);
items[10]=new Shop("Samp", (int) 12.00);
items[11]=new Shop("Dress", (int) 200.00);
items[12]=new Shop("Pants", (int) 150.00);
items[13]=new Shop("Shoes", (int) 400.00);
items[14]=new Shop("Socks", (int) 25.00);

    for (Shop item : items) {
        System.out.println("Item: " + item.item + ", Price:" + item.price);
    } 

    }

class Shop


String item;
int price;

public Shop(String item,int price)

this.item=item;
this.price=price;

When following tutorials on Daniweb, you might have run into one that requires knowledge about Dependency Injection as a prerequisite. People might also sometimes use the term Inversion of Control interchangeably with DI.

These terms are related to one another, but they are not the same. In this article, we will learn the basics of Dependency Injection and I will attempt to explain it in the simplest way possible.

Goals

At the end of the article, you would have learned:

1. What dependency injection is.

Prerequisite Knowledge

1. Basic Java.

Dependency Injection vs. Inversion of Control

IoC refers to a programming principle where a framework calls your code instead of your code interacting with a particular device by itself. Because the framework is directly interacting with the device, but not your code, the control has been inverted from you to the framework.

An example of this is the Android Activity class, where you are mostly responsible for defining what to do at lifecycle callbacks, such as onStart(), or onPause(). The Android system is responsible for calling your code when your App is started or paused.

The opposite of IoC is when you open a database connection yourself, execute whatever queries that you need, and then closing the connection. You are in control here and no framework is calling your code.

DI is a little different to IoC because with DI, you are only giving up the control of the creation of dependencies. You simply state what you need, and then an injector will provide the dependencies to you. You do not need to know what an injector is in this basic article. Furthermore, you can simply think of them as classes that provide dependencies to your class.

Common types of Dependency Injection

The three most common types of DI are:

1. Constructor injection: the DI framework or injector will provide dependencies to the constructor on object creation.

    class Foo {
   
       //Foo depends on Bar
       private final Bar bar;
   
       //Injector will provide an instance of Bar
       //on creation of Foo
       Foo(Bar bar){
           this.bar = bar;
       }
    }

2. Setter injection: The DI framework or injector class will call the setter method, providing the dependency after the object has been created.

    class Foo {
       private Bar bar;
   
       public void setBar(Bar bar) {
           this.bar = bar;
       }
    }

3. Field Injection: The DI framework or injector will set the value for the field directly via reflection. This type of DI incur a performance cost, so certain DI frameworks, such as Dagger 2, do not support it.

    class Foo {
       private Bar bar;
    }

There is also another type of DI called Interface Injection, but I have not seen it used widely, so I would not cover it here.

Manual Dependency Injection

Sometimes, Manual DI might be brought up. This refers to you creating your own dependency container, putting you in charge of managing the shared dependencies among your classes. This approach makes sense if you do not want to bring in a DI framework as a dependency, or maybe your app is small. Since this topic deserves its own tutorial, I will have to discuss in a separate article.

Most of the time, I prefer to use a DI framework because I would rather focus on providing features in my application instead of re-inventing the wheel.

Java annotations are often used to provide extra information for compilers, IDEs, and build tools. The extra information is often used to enhance the development cycle, such as reducing boilerplate, eliminating repetitive code, or warning against unsafe usage or mistakes.

This tutorial aims to teach you the basic amount of knowledge about annotations, so that you can identify them and know what to search for in your coding journey.

Goals

At the end of the tutorial, you would have learned:

1. What Java annotations are.
2. When to use Java annotations.

Tools Used

1. A Java IDE. IntelliJ CE version #IC-221.6008.13 was used for this tutorial.
2. Java 18 was used.

Prerequisite Knowledge

1. Basic Java.

Annotation Interface vs Annotation

Before anything else, let us get a common source of confusion regarding terminology out of the way. What is commonly called Annotation by Java developers can refer to two different things:

1. Annotation Interface: blueprints for creating instances of Annotations. For example:

    public @interface Override {
    }

2. Annotation: instances of Annotation Interfaces that can used to mark elements in your code. For example, two instances of the Annotation Interface @Override are used below.

    @Override
    public String toString() {
       return super.toString();
    }
   
    @Override
    public boolean equals(Object obj) {
       return super.equals(obj);
    }

Annotation Interface

Most of the rules for interfaces also apply to annotation interfaces. However, a few key differences are:

1. The keyword interface must be preceded by an @ character.

    interface Foo {}
    @interface Bar {}

2. An Annotation Interface can never be generic.

    interface Foo<T> {} //legal
    @interface Bar<T> {} //illegal

3. The direct super interface of all annotation interfaces is always java.lang.annotation.Annotation.

4. Annotation interfaces cannot use the extends clause.

Annotation Interface Members

The body of Annotation Interfaces can only contain the members listed below:

1. Interface declarations.

2. Class declarations.

3. Constants.

4. Method declarations. Each method declared is called an element.

    interface Foo extends java.lang.annotation.Annotation {}
    @interface Bar {
       interface Animal {} //interface
       @interface Foo {} //annotation interface is also an interface
       class Dog {} //clas declaration
       int NUM = 1; //constant
   
       //method without default value. Instances must provide a value.
       int customMethod();
   
       //method with default value.
       //Instances are not required to provide a value
       int customMethod2() default 2;
    }

Annotation Interface Elements (Methods)

Elements of an Annotation Interface have even further restrictions. Methods must return one of the types below:

1. A primitive type
2. String.
3. Class or an invocation of Class.
4. An enum class type.
5. An annotation interface type.
6. An array type whose component type is one of the preceding types.

The method signature cannot override any method from Object or java.lang.annotation.Annotation.

Marker Annotation Interface

An Annotation Interface without any element is called a marker annotation interface.

public @interface Override {
}

Single Element Interface

An Annotation Interface with only one element is called a single-element annotation interface. If you use the method name value in a single-element annotation interface, then the caller is not required to specify the element name when instantiating your annotation interface.

@interface Name {
   String value();
}

@interface Age {
   int age();
}

@Name("Annie") //the element name "value" is not required
@Age(age = 1) //the element name "age" is required
class Person {}

Default Java Annotations

Java SE comes with many pre-defined annotations. You are not required to know them all, but the most important ones are:

1. @Deprecated: Mark part of your code as deprecated, so other developers will avoid using this part of your code.

2. @Override: You should always use this annotation when overriding a method. This enables the compiler and your IDE to warn you in cases where you think that you are overriding a super method, but maybe a typo created a completely new method instead of overriding.

3. @Target: This annotation can be used on other annotations to restrict the type of constructs that the other annotation be applied to. For example, the @Target(ElementType.Method) used on the @Override annotation interface indicates that @Override can only be used on methods.

    @Target(ElementType.METHOD)
    public @interface Override {
    }

When are Annotations Used

The main purpose of annotations are to provide extra information in your code. Different actors such as compilers, build tools, IDE, or other plugins use this extra information to provide something useful (hopefully) when compiling your code. A couple of examples include:

1. Java SE: @Override is used to reduce mistakes by developers.
2. Project Lombok: A lot of its features are delivered via annotations. getters and setters are automatically generated by Lombok if you annotate any field with @Getter or @Setter. This lessens the amount of code that you have to write. Less code to look at makes your code easier to read.
3. Spring framework: @Controller, @Service, @Repository are used to mark classes as fulfilling architectural duties, so Spring can set up the environment correctly.
4. Vaadin framework: @Route is used to configure navigation routes.
5. Android: @Insert, @Update, @Query, and @Delete are used on DAO methods, so that the compiler will generate appropriate CRUD code for you.

Annotations are not language constructs limited to Java. Other languages also employ the same feature. For example, decorators in Typescript also serve the same purpose as Java annotations.

1. Create an array of item names. Use the following item names: Bread, Milk, Butter, Chips, Honey, Soap, Towel, Carrots, Beans, Samp, Dress, Pants, Shoes, Socks.
2. Create an array of item prices. Use the following item prices: 15.50, 12.00, 56.00, 20.00, 45.00, 7.00, 75.00, 8.00, 5.00, 12.00, 200.00, 150.00, 400.00, 25.00.
3. Display every item name and its corresponding price. See the sample output given.
4. Print the average price of all the items.
5. Find and display the price of a specific item
   a. Read in the name of the item.
   b. Loop through the items array and look for the specific item.
   c. If the item is found, display the price of the item.

Bread - R15.5
Milk - R12.0
Butter - R56.0
Chips - R20.0
Honey - R45.0
Soap - R7.0
Towel - R75.0
Carrots - R8.0
Beans - R5.0
Samp - R12.0
Dress - R200.0
Pants - R150.0
Shoes - R400.0
Socks - R25.0

Display the average price of all the items
The average price of all the items is R73.0

Find and display the price of a specific item Sample input and output
Sample run 1
Sample run 2
Item Look-up
What item are you looking for?
Dress
The price of item Dress is R200.0
Item Look-up
What item are you looking for?
hjgjg
Item hjgjg is not stocked in the shop.

I am developing android java filemanager app.. I used checkbox to check 1/file.mp4
2/folder(files+sub folders)
.

How can i add copy paste feature for checked 1, 2 file folder fully at same time ?like -google filemanager app..

Advance Thanks

    //stack class also containing the intopostfix method
   import java.util.*;
    public class Stack 
    {   int i,j;
char postfix[];
char stack[];
int top;
String post;
public Stack(int n)
{
    stack=new char[n];
    top=-1;
}
public void push(char item)
{
    if(top>=stack.length)
        System.out.println("Stack overflow");
    else
    {
        stack[++top]=item;
    }
}
public char pop()
{
    if(top==-1)
    {       System.out.println("Stack underflow");
            return 0;
    }
    else
        return stack[top--];
}
boolean isAlpha(char ch)
{
    if((ch>='a'&&ch<='z')||(ch>=0&&ch<='9'))
        return true;
    else 
        return false;

}
boolean isOperator(char ch)
{
    if(ch=='+'||ch=='-'||ch=='*'||ch=='/')
        return true;
    else return false;

}

void intopost(String str)
{
    postfix=new char[str.length()];
    char ch;

    j=0;

    for(i=0;i<str.length();i++)
    {
        ch=str.charAt(i);
        if(ch=='(')
            push(ch);
        else if(isAlpha(ch))
        {
            postfix[j++]=ch;
        }
        else if(isOperator(ch))
        {
            push (ch);
        }
        else if(ch==')')
        {
            while((pop())!='(')
                    {
                        postfix[j++]=pop();
                    }
        }

    }

}
void disp()
{
    for(i=0;i<postfix.length;i++)
    {   
        System.out.print(postfix[i]);
    }
}
}

Thank you in advance.

ClientCode:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;
import java.net.SocketException;

public class Client {

    public static void main(String[] args) {
        int N;
        Scanner sc=new Scanner(System.in);
        Socket cs=null;
        BufferedReader bfr=null;
        PrintWriter pw=null;
        try{
            cs=new Socket("localhost",5000)  ;
            InputStreamReader isr=
                    new InputStreamReader(cs.getInputStream());
            bfr=new BufferedReader(isr);
            pw=new PrintWriter(cs.getOutputStream());
            System.out.println("S-a setat reteaua!");
            for(;;){

                System.out.print("Cuvantul care trebuie tradus:");
                String cuvant=sc.nextLine();
                //daca este STOP : se va deconecta
                if(cuvant.equals("STOP")) {pw.println(""); pw.flush();break;}
                else  {pw.println(cuvant); pw.flush();}
                //Citim raspuns server:
                String textIn=bfr.readLine();
                if(textIn==null)break;
                System.out.println(textIn);
            }//for;;
        }catch( IOException e){
            e.printStackTrace();
        }
        System.out.println("Clientul s-a deconectat!");
    }//main
}

ClientHandler code:

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.ArrayList;
import java.net.SocketException;


//Clasa firului de execuie pentru tratarea clientului conectat la server:
class FirClient extends Thread {
    private Socket cs;
    private BufferedReader bfr;
    private PrintWriter pw;
    ArrayList<String> listacuvinte;//la creare firului incarcam datele

    // din fisier intr-un ArrayList
    public FirClient(Socket cs) {
        try {
            this.cs = cs;
            pw = new PrintWriter(cs.getOutputStream());
            InputStreamReader isr =
                    new InputStreamReader(cs.getInputStream());
            bfr = new BufferedReader(isr);
            //incarcam fisierul cuvinte .txt in ArrayList:
            listacuvinte = new ArrayList<String>();
            System.out.println("Se copiaza fisier in al");
            FileReader f = new FileReader("date.txt");
            BufferedReader bf = new BufferedReader(f);
            for (; ; ) {
                String s = bf.readLine();
                if (s == null) break;//s-a terminat fisier
                listacuvinte.add(s);
            }
            bf.close();
            f.close();
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(1);
        }
    }

    public void run()
    {
        try{
            for(;;){
                String cuvant = bfr.readLine();
                if(cuvant == null)break;
                if(cuvant.equals(""))break;
                //cautare cuvant in ArrayList:
                boolean gasit=false;
                for(int i=0;i<listacuvinte.size();i+=2){
                    if(listacuvinte.get(i).equals(cuvant)){
                        String crt= listacuvinte.get(i+1);
                        gasit=true;
                        break;
                    }

                }

            }//for;;
        }catch(final Exception e){e.printStackTrace();}
    }//run
}

ServerCode:

import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;


public class Server {

    public static void main(String[] args) {
        System.out.println("Am pornit server...");
           try{
            ServerSocket ss=new ServerSocket(5000);
            for(;;){
             Socket cs=ss.accept();
             FirClient firPtClient=new FirClient(cs);
             firPtClient.start();
             System.out.println("Avem o conectare!");
            }//for;;
           }catch(Exception e){
               e.printStackTrace();
           }


    }

}

public class Ukoly {

    protected String predmet;
    protected String poznamka;
    protected String stav;
    protected int den;
    protected int mesic;
    protected int rok;
    protected int znamka;

    public Ukoly(int den, int mesic, int rok, String predmet, String poznamka, String stav, int znamka) {
        super();
        this.den = den;
        this.mesic = mesic;
        this.rok = rok;
        this.predmet = predmet;
        this.poznamka = poznamka;
        this.stav = stav;
        this.znamka = znamka;
        }
    public Ukoly() {
        // TODO Auto-generated constructor stub
    }
    public  void setPredmet(String pred) {
        this.predmet = pred;
    }
    public void setPoznamka(String pozn) {
        this.poznamka = pozn;
    }
    public void setStav(String st) {
        this.stav = st;
    }
    public void setDen(int den) {
        this.den = den;
    }
    public void setMesic(int mesi) {
        this.mesic = mesi;
    }
    public void setRok(int rok) {
        this.rok = rok;
    }
    public void setZnamka(int zn) {
        this.znamka = zn;
    }
    public String getPredmet() {
        return this.predmet;
    }
    public String getPoznamka() {
        return this.poznamka;
    }
    public String getStav() {
        return this.stav;
    }
    public int getDen() {
        return this.den;
    }
    public int getMesic() {
        return this.mesic;
    }
    public int getRok() {
        return this.rok;
    }
    public int getZnamka() {
        return this.znamka;
    }
    @Override
    public String toString() {
        return "Ukoly [predmet=" + predmet + ", poznamka=" + poznamka + ", stav=" + stav + ", den=" + den + ", mesic="
                + mesic + ", rok=" + rok + ", znamka=" + znamka + "]";
    }


}





import java.util.ArrayList;
import java.util.Scanner;


public class Denik extends Ukoly{

    public Denik(int den, int mesic, int rok, String predmet, String poznamka, String stav, int znamka) {
        super(den, mesic, rok, predmet, poznamka, stav, znamka);

    }

    public static void main(String[] args) {

        ArrayList<Ukoly> ukol = new ArrayList<>();
        @SuppressWarnings("resource")
        Scanner sken = new Scanner(System.in);
        int vyber;
        int vyber1 = 2;
        int vyber2;
        int vyber3;
        int vyber4;
        String datum;



        while (vyber1 == 2) {

            Ukoly novy = new Ukoly();


            System.out.println("Stisknte 1 pro oteven seznamu kolu nebo 2 pro pidvn kol.");
            vyber = Integer.parseInt(sken.nextLine());
            if (vyber == 1) {



                      }
            if (vyber == 2) {

                System.out.println("Zadejte z jakho pedmtu kol je: ");
                novy.setPredmet(sken.nextLine());
                System.out.println("Zadejte datum odevzdn ve tvaru 20.01.2000: ");
                datum = sken.nextLine();
                novy.setDen(Integer.parseInt(datum.substring(0, 2)));
                novy.setMesic(Integer.parseInt(datum.substring(3, 5)));
                novy.setRok(Integer.parseInt(datum.substring(6, 10)));
                System.out.println("Zde mete zadat poznmku: ");
                novy.setPoznamka(sken.nextLine());
                System.out.println("Zde zadejte stav kolu(vypracovn, ale neodevzdn/nevypracovn): ");
                novy.setStav(sken.nextLine());
                System.out.println("Zde si zapite poku mte z kolu njakou znmku(ve tvaru 1/2/3/4/5/0): ");
                novy.setZnamka(Integer.parseInt(sken.nextLine()));
                ukol.add(novy);

                System.out.println("Chce zobrazit svj kol/y kter m zapsan? Pokud ANO stiskni 1, pokud NE stiskni 2");
                vyber2 = Integer.parseInt(sken.nextLine());

                if (vyber2 == 1) {
                    for (int i1 = 0; i1 < ukol.size(); i1++)

                        System.out.println(ukol.get(i1));
                }

                if (vyber2 == 2) {

                }

            }

            System.out.println("Byli to vechny tv koly(stiskni 1), nebo si chce zapsat dal kol?(stiskni 2) ");
            vyber1 = Integer.parseInt(sken.nextLine());
            if (vyber1 == 1) {

                System.out.println("Chce vypsat a seadit vechny sv koly? Pro ANO stiskni 1, pro NE stiskni 2.");
                vyber3 = Integer.parseInt(sken.nextLine());
                if (vyber3 == 1) {

                    System.out.println("Chce seadit koly podle pedmtu(stiskni 1) nebo data odevzdn(stiskni 2)?");
                    vyber4 = Integer.parseInt(sken.nextLine());
                    if (vyber4 == 1) {




                    }
                    if (vyber4 == 2) {



                    }
                }
                if (vyber3 == 2) {
                    System.out.println("Dobe.");
                }

            }


        }
    }

Currently it mixes data and I see that it because of this.

package com.Main.tile;

import com.Main.GamePanel;
import com.Main.UtilityTool;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class TileManager {
    GamePanel gp;
    public Tile[] tile;
    public int mapTileNum[] [];

    public TileManager(GamePanel gp){
        this.gp = gp;
        tile = new Tile[10];
        mapTileNum = new int [gp.maxWorldCol] [gp.maxWorldRow];

        getTileImage();
        loadMap("/maps/world01.txt");
    }
    public void getTileImage(){

            setup(0, "grass", false);
            setup(0, "wall", true);
            setup(0, "water01", true);
            setup(0, "earth", false);
            setup(0, "tree", true);
            setup(0, "sand", false);

    }

    public void setup(int index, String imageName, boolean collision){

        UtilityTool uTool = new UtilityTool();

        try {
            tile[index] = new Tile();
            tile[index].image = ImageIO.read(getClass().getResourceAsStream("/tiles/"+imageName+".png"));
            tile[index].image = uTool.scaleImage(tile[index].image, gp.tileSize, gp.tileSize);
            tile[index].collision = collision;

        } catch (IOException e){
            e.printStackTrace();
        }
    }
    public void loadMap(String filePath){
        try{
            InputStream is = getClass().getResourceAsStream(filePath);
            BufferedReader br = new BufferedReader(new InputStreamReader(is));

            int col = 0;
            int row = 0;

            while(col < gp.maxWorldCol && row < gp.maxWorldRow){
                String line = br.readLine();
                while(col < gp.maxWorldCol){
                    String numbers[] = line.split(" ");

                    int num = Integer.parseInt(numbers[col]);
                    mapTileNum[col] [row] = num;
                    col++;
                }
                if(col == gp.maxWorldCol){
                    col = 0;
                    row++;
                }
            }
            br.close();
        }catch(Exception e){

        }
    }
    public void draw(Graphics2D g2){
        int worldCol = 0;
        int worldRow = 0;

        while(worldCol < gp.maxWorldCol && worldRow < gp.maxWorldRow){
            int tileNum = mapTileNum[worldCol] [worldRow];

            int worldX = worldCol * gp.tileSize;
            int worldY = worldRow * gp.tileSize;
            double screenX = worldX - gp.player.worldX + gp.player.screenX;
            double screenY = worldY - gp.player.worldY + gp.player.screenY;

            if(worldX + gp.tileSize > gp.player.worldX - gp.player.screenX &&
               worldX - gp.tileSize < gp.player.worldX + gp.player.screenX &&
               worldY + gp.tileSize > gp.player.worldY - gp.player.screenY &&
               worldY - gp.tileSize < gp.player.worldY + gp.player.screenY) {
                g2.drawImage(tile[tileNum].image, (int)screenX, (int)screenY, null);
            }
            worldCol++;
            //x += gp.tileSize; DISABLE FOR STABILITY
            if(worldCol == gp.maxWorldCol){
                worldCol = 0;
                //x = 0;
                worldRow++;
                //y += gp.tileSize;

            }
        }
    }
}

and it always shows the error:

Exception in thread "main" java.lang.IllegalArgumentException: input == null!
at java.desktop/javax.imageio.ImageIO.read(ImageIO.java:1358)
at com.Main.tile.TileManager.setup(TileManager.java:44)
at com.Main.tile.TileManager.getTileImage(TileManager.java:29)
at com.Main.tile.TileManager.<init>(TileManager.java:24)
at com.Main.GamePanel.<init>(GamePanel.java:30)
at com.Main.Main.main(Main.java:13)