48 Tutorial Topics
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 | ## Introduction ## In Android Studio, we can run multiple tests in parallel across multiple devices using the dropdown menu.  Running instrumented tests this way is very convenient during development, but there is a problem with this method when your tests are run on a remote build server: * … |
| | ## Introduction ## In the last tutorial, we learned [how to send messages to a RabbitMQ queue](https://www.daniweb.com/programming/web-development/tutorials/538621/how-to-send-messages-in-rabbitmq). In this tutorial, we will learn how to consume those messages in Kotlin. ## Goals ## At the end of the tutorial, you would have learned: 1. How to use the RabbitMQ Java … |
| | ## Introduction ## In the [last Selenium tutorial](https://www.daniweb.com/programming/software-development/tutorials/538447/basic-interactions-with-web-elements-in-selenium), 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: …  |
| | ## Introduction ## 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 … |
| | ## Introduction ## 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 … |
| | ## Introduction ## 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 … |
| | ## Introduction ## While creating Selenium tests, you might have found that inspecting elements manually using the web browser’s 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 … |
| | ## Introduction ## 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 don’t*) or build e2e tests for your website. In this tutorial, we … |
| | ## Introduction ## 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 … |
| | ## Introduction ## When working on Java applications, it is very likely that you will run into JDBC at some point. While you are unlikely to have to work directly with JDBC when using frameworks, it is still important to know how the connection is established and how queries are … |
| | ## Introduction ## 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 … |
| | ## Introduction ## On the android platform, widgets provide a quick way to interact with your Apps. They are extremely useful at providing quick information without the user launching the app Activities themselves. Common use cases for homescreen widgets are weather, email, or banking information. In this tutorial, we will … |
| | ## Introduction ## When working with WorkManager, it is important to know how to provide input data to your Workers. In this tutorial, we will learn how to provide basic input data to a Worker as well as when Workers are chained together. ## Goals ## At the end of … |
| | ## Introduction ## When using Navigation Components, you might have wondered how to pass arguments between destinations. We will learn how to do just that in this tutorial. This tutorial also builds upon the [Basic Navigation](https://www.daniweb.com/programming/mobile-development/tutorials/536923/android-native-how-to-use-navigation-component#post2282945) tutorial, so if you are not familiar with Navigation Components, I would recommend you … |
| | ## Introduction ## When working on Android with Kotlin, you might have ran into property delegates on a few occasions, such as `activityViewModels()` from `androidx.fragment.app` or `remember()` from `androidx.compose.runtime`. In this tutorial, we will learn what property delegates are and how to create them ourselves. ## Goals ## At the … |
| | ## Introduction ## All TextView objects have a special attribute called `textAppearance`. This attribute can be used to set the style for text content in a TextView without affecting other styling attributes on the same TextView object. In this tutorial, we will learn how to apply `textAppearance` to TextView objects. … |
| | ## Introduction ## One of the best debugging tools in Android Studio is the *live database inspector*. It allows developers to peek at the current state of the database and even run queries against it. In this tutorial, we will learn how to use it to debug a local SQLite … |
| | ## Introduction ## When localizing your application, `ResourceBundle` can be a great way to load Strings from different locales. The only concrete implementation of ResourceBundle is `PropertyResourceBundle`, which allows us to load static Strings from a text file. Because `.properties` is a common file extension used for ResourceBundles, creating ResourceBundle … |
| | ## Introduction ## Junit is a popular framework to create tests for Java applications. Although individual unit tests are mostly straightforward, integration and functional tests are a little bit more involved because they usually require multiple components working together. For that reason, understanding the life cycle of Junit tests can … |
| | ## Introduction ## When collecting a stream, the `groupingBy()` Collector(`java.util.stream.Collector`) can be used to put data into different groups based on specified conditions. `groupingBy()` is a little bit more complicated to use than [partitioningBy()](https://www.daniweb.com/posts/jump/2280662) because the key can be of any type, whereas with `partitioningBy()`, the keys must be of … |
| | ## Introduction ## Whenever we want to modify numbers from multiple threads running concurrently, such as modifying a counter, one of the best options is to use the AtomicX classes. The most basic numeric atomic classes are AtomicInteger and AtomicLong. In this tutorial, we will learn how to use the … |
| | ## Introduction ## If you are a Java developer coming to Kotlin, you might have wondered how to use a language construct that is similar to the try-with-resource statement in Java to automatically close Autocloseable/Closeable resources for you. Luckily, Kotlin provides the inline extension function `use()` that provides similar functionality … |
| | ## Introduction ## In Java, a common way to express a type that is a combination of two or more types is to just create an interface that extends the other types. The problem with this approach is that your code might be littered with interface declarations, polluting your code … |
| | ## Introduction ## In Kotlin, we can extend classes without subclassing via extension functions and extension properties. This feature is useful whenever we want to extend 3rd party libraries or final classes. In this tutorial, we will learn what extension functions and extension properties are, and how to create our … |
| | ## Introduction ## `launch()` and `async()` are two of the most common coroutine builders to use in Kotlin, but they are somewhat different in usage. `launch()` returns a `Job` object, which can be used to cancel or perform other operations on the underlying coroutine. If our coroutine lambda returned a … |
| | ## Introduction ## In this tutorial, we will look at the RxJava `mergeWith()` and `concatWith()` operators. Amongst others, they are used to combine Observables together. All of the RxJava operators have ambiguous names, and behave differently, so let us take a look at 2 operators, `mergeWith()` and `concatWith()`, to see … |
| | ## Introduction ## RxJava 3 includes 5 core classes: 1. Flowable, 2. Observable, 3. Single, 4. Completable, 5. Maybe. This tutorial aims to teach the basic concepts behind Observable, which serves as a foundation for understanding the other 4 classes. ## Goals ## At the end of the tutorial, you … |
| | ## Introduction ## With coroutines in Kotlin, we are able to execute suspending functions without blocking the current thread. By default, most coroutine builder functions use the `Dispatchers.Default` context, but it is also possible to use other implementations of `CoroutineContext`. In this tutorial, we will learn about the 2 `CoroutineDispatchers`: … |
| | ## Introduction ## The `java.nio.file.Files` class includes many convenient methods to read file attributes, but sometimes these convenient methods just are not enough to meet our needs. In this tutorial, we will go over 5 ways to use the `Files` class to read file attributes so you can choose the … |
| | ## Introduction ## When working with an application with a global user base, there is usually a need to display text, numbers, currency, date, and time in multiple localized formats. For example, the **en-US** (*English-USA*) version of the date September 22, 2021 is written as 22 сентября 2021 г. when … |
| | ## Introduction ## In Android development, the current recommended library for Dependency Injection is Hilt. The most obvious benefits of using Hilt are reduced boilerplate code and lifecycle-aware components(*and their associated annotations*). Hilt is a great library, but it is not perfect. Hilt is built on top of Dagger 2, … |
| | ## Introduction ## In Java 8, `@Repeatable` was introduced and this is the recommended way to create repeating annotations. We still have to create a holder Annotation(*annotation that holds an array of other annotations*), but we no longer have to declare the holder Annotation at the callsite. This tutorial aims … |
| | ## Introduction ## Java 15 introduced Text Blocks. The main reason behind Text Blocks is that programmers can write multiline strings without having to specify escapes for the most common scenarios. ## Goals ## At the end of this tutorial, you would have learned: 1. How to store multiline String …  |
| | ## Introduction ## Before Java 8, methods had to throw an exception or return `null`, with neither of which approaches were perfect. Optional, OptionalInt, OptionalLong, and OptionalDouble were introduced in Java 8 to represent values that might possibly be `null`. Optionals have two internal states, **empty** or **present**. An Optional … |
| | ## Introduction ## There are many ways to design secure Java objects. In this tutorial, we are going to learn how to create secure Java objects by understanding **Accessibility**, **Extensibility**, and **Immutability**. ## Goals ## At the end of this tutorial, you would have learned: 1. Understand how and why … |
| | ## Introduction ## In this tutorial, we will focus on how to manage IO permissions to read, write, and delete local files using the `SecurityManager` class. ## Goals ## At the end of this tutorial, you would have learned: 1. What policy files are and how to use them. 2. … |
| | ## Introduction ## Java 14 was released with a new type of expression called Switch Expression. Its syntax is similar to that of the Switch Statement, with a few differences. In this tutorial, we will walk through concepts related to the Switch Expression and learn how to use it. ## … |
| | ## Introduction ## In this tutorial, we are going to learn how to create a Java module by hand. ## Goals ## At the end of this tutorial, you would have learned: 1. What a `module-info.java` file is. 2. How to compile a module. 3. Describing a module. ## Prerequisite … |
| | ## Introduction ## This tutorial introduces the `CyclicBarrier` class and teaches you how to use it. ## Goals ## At the end of this tutorial, you would have learned: 1. How to use `CyclicBarrier` to synchronize tasks across multiple threads. ## Prerequisite Knowledge ## 1. Intermediate Java. 2. Basic knowledge … |
| | ## Introduction ## `partitioningBy()` collects a `Stream` into a `Map`. In this tutorial, we will compare the two different `partitioningBy` methods and learn how to use them. ## Goals ## At the end of this tutorial, you would have learned: 1. What `Collectors.partitioningBy` does and how to use it. ## … |
| | ## Introduction ## Based on the 2020 Java Ecosystem survey from Jetbrains, 75% of Java developers are still using JDK 8. JDK 11 introduces `HttpClient`, which replaces the legacy `HttpURLConnection` API. For this tutorial, we will build a `HttpClient` that consumes the free Cat Facts API. ## Goals ## At … |
| | ## Introduction ## This tutorial teaches you how to implement the Type-safe Builder pattern using Kotlin. This pattern allows developers to create declarative and concise DSLs. Our implementation will be a Burger Builder that enables our users to create Burger objects expressively. ## Goals ## At the end of the … |
 | Yes, you've been told it's dead, gone and to move off this old beast of a system from 1998 but here you are, tasked with fixing an old legacy app so let me share that I've been there and how I got around some of the issues. These are: 1. …  |
 | Hello everyone! As some of you may know, Eclipse Luna appears to be broken for users of Kali Linux. There is a simple fix for that > Assuming that you have installed Eclipse Luna locate eclipse.ini `sudo nano eclipse.ini` add the following 2 lines before `--launcher.appendVmargs` --launcher.GTK_version 2 press `ctrl …  |
 | **Modifications Required for VB6 Applications to Work on Vista/7** Thanks to Hassan Basri in VBForums **Application Changes** - Remove SendKeys calls and replace them with API code. - Use the HKEY_CURRENT_USER in the registry for the settings of your application. - Do not write to HKEY_LOCAL_MACHINE. - If you are …  |
 | # Introduction # A recurring problem many newcomers face when tackling C++ is the compilation process, from sources to binaries. This tutorial will detail that process. It will be especially useful for people only familiar with higher-level languages (if any), but veterans of one or more native languages (C, Fortran, … |
 | The aim of this tutorial is to save burgeoning self taught developers some of the early pitfalls that lurk on the road to programming enlightenment. It will attempt to do this by distilling the last 50 years of software engineering philosophy into a relatively short single tutorial, applying the concepts … |
 | After spending some time on JSP section of this forum as many before me, I come to the conclusion that we are in need of "proper" tutorial on this topic. This tutorial is not intended to teach you everything from top to bottom, it is just a starting point to … |