• Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Online Compiler in Java

    If you Google "writing a compiler" you will find lots and lots of tutorial material that will tell you what you need. It shouldn't be difficult to extend it to …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Coding

    To be brutally honest, it seems like you're not ready to tackle a compicated GUI program yet. You'll get far better long-term results by going back and learning the basics …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Coding

    You will probably find it easier to use the next method `public void setSelectedIndex(int index)` where index is 0 for the first tab, 1 for the second etc
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Coding

    Assuming you asre using a JTabbedPane (if not, you should be), you can learn how to respond to a button click here http://docs.oracle.com/javase/tutorial/uiswing/components/button.html and how to work with tabbed panes …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Why we use Interface

    Think about this example. The `Comparable` interface defines a method `compareTo` that compares two objects so they can be sorted etc. Many classes implement this interface - eg Integer, String …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in java SE 7u67

    Was that 64 bit NetBeans? What's wrong with Java 8 (the current version)?
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Eclipse IDE

    Yes, they are all the old versions. Just download the latest (Luna) and ignore all the others.
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in set image as Background

    You have used absolute coordinates to place your labels, which is OK if you will never run this on any device with a different screen resolution. In particular, run it …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java help needed

    Small point: Java programming conventions prefer the use of "camel case" rather than underscores, so accountBal would be better advice than account_bal.
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in set image as Background

    Raj: How do you intend to keep the other components in front of the image JLabel? Which layout manager would you use to place components overlapping the image JLabel?
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in I/O of txt file

    Without seeing the relevant code there's absolutely nothing I can say.
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in I/O of txt file

    Don't worry about indexOf, replaceAll is the better option. If you use indexOf you will also have to a load of substrings to do the replacement. replaceAll is the easiest …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in I/O of txt file

    You're looking for the abbreviations anywhere in the String, so cpmparteTo isn't useful for that. Have a look at the String class, `indexOf` and `replace` methods.
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in I/O of txt file

    Yes. But you don't need to process the whole message in one go, just read/process/write one line at a time. Its easier that way.
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in I/O of txt file

    If you think about it... You need to know what all the abbreviations are before you can start processing the text file. So the overall plan needs to be: read …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    > About "Public Static Variables" what are the issues involved with using them. [Here's](http://c2.com/cgi/wiki?GlobalVariablesAreBad) a pretty decent discussion of this topic.
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    The static "global" variable is a perfectly valid solution... maybe not the best O.O practice, but OK in this context. It's certainly the easiest to code! As for other speedups, …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    I did say there is a synchronising lock associated with each file. That's essential to avoid concurrent updates to one file. But it's not a global lock, and won't prevent …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    You can use one connection with multiple SQL commands and strings. Just connect once and use multiple createStatements. Access the connection just like any other Java variable - pass it …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Selection Sort help

    Yup, that's what you get when you print an array - it's the toString() method that arrays inherit from Object - the bracket says its an array, the I says …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Selection Sort help

    Yup, that's what you get when you print an array - it's the toString() method that arrays inherit from Object - the bracket says its an array, the I says …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Selection Sort help

    The code on lines 21-36 sorts the data (or it will, when you've fixed the bug), so it has to be after that. The main method ends on line 38, …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    > The synchonize part is when you check if the file is locked. If it is locked, exit the synchronized and go to sleep. If the file is not lock, …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Selection Sort help

    If you want to display the output (the contents of the array at the end), and you know loops and print, then what exactly is your question?
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    If you keep a master table with the right number of complete decks, you can simply get a shuffled deck by selecting all the records in the master in random …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in pseudo perfect number

    There are lots of people here who will freely give their time to help you become the best Java programmer you can be. There's nobody here who is interested in …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    You simply need some arbitrary object xxx associated in some way with that file, then your file writing method needs a synchronised (xxx) { // update the file } so …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    That changes everything. Thousands of clients to 60 files means massive contention for each file, and FIFO queueing is appropriate. But if it's a thousand files then there will be …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in set image as Background

    JPanel is very standard stuff. Just add all your controls to the JPanel, then add the JPanel to your JFrame. Later on you will discover all kinds of reasons why …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in set image as Background

    You create a subclass of JPanel and override its paintComponent method to draw your image when the panel is repainted. Then add your components to the panel to display then …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    As I understand it 11/12 is a standard Java server socket, creating a thread to handle each client socket as it connects. This is all about the threading - with …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    First mistake is creating a new connection for each statement. Opening a connection is expensive. Just open a connection when starting the program and re-use that throughout. Secondly: I wasn't …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    Database processing over a network connection is exactly the kind of thing SwingWorker is good for, so that's OK. But 7 seconds for 104 tiny records? That sounds crazy! If …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    That's a very good point. A standard Fisher-Yates / Knuth Shuffle on a 52 element array runs in microseconds.
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    OK, that's exactly the scenario I guessed in my first post. You cannot do it like that becuase of the way the EDT works. SwingWorker is definitely what you should …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Copy from text file to Object type arrayList in Java

    Nice example. You can push the Stream usage a bit further, depending on the overall requirements, along the lines of: Files.lines(Paths.get("studentTest.txt")) .map(line -> line.split(":")) .filter(parse -> parse.length == 2) .map …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    1. With the wait before getting the input stream the process hangs with a 210k file on my machine (win7 64, Java 8). No surprise there. 2. No, there really …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Show a message while a method is running

    Are you trying to do this? actionPerformed ... show "busy" message do some stuff remove "busy" message if so... Everything to do with Swing (eg painting the screen, running actionPerformed …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    OK, sorry to hear about the 1.6 requirement - I gues your client/boss knows that it's out of support and has security problems that will never be fixed? I ran …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    > the server has about 60 texts files later... > I have almost 1000 files which is it?
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    Create a LinkedBlockingQueue for each file. When a client sends data, just add it to the appropriate queue. For each queue, create a thread that loops taking the top item …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in get position of the maximum number in a singly linked linked list

    You already have a method to find the largest value. All you need is exactly that same logic, plus keep a count of the position as you loop. Each time …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    ... and a small ps - a tidied-up version of your getStringFromInputStream private static String getStringFromInputStream(InputStream is) { StringBuilder sb = new StringBuilder(); try (BufferedReader br = new BufferedReader(new InputStreamReader(is, …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    Just for reference... I ran this code (with try/catch, imports etc), using your `getStringFromInputStream` method unchnaged, against a 210k text file with perfect results... Runtime r = Runtime.getRuntime(); Process pr …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    Yes, it certainly looks like a OS limit on the sysout buffer. Can you post your latest code because what you are trying to do is a perfectly normal thing …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    Java Stream buffer size may affect the efficiency of your execution, but it won't change whether it works or not. Maybe the problem is that you waitFor the process to …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    That code should be able to read the process output up to the limit of a single String. Maybe it's the logger that's the problem? Try just printing the string …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Java run windows system command and get result

    What code are you using to process the output stream from your process?
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Thousand threads write to one text file simultaneously

    The obvious choice is a LinkedBlockingQueue. As the API doc says: > BlockingQueue implementations are thread-safe. All queuing methods achieve their effects atomically using internal locks or other forms of …
  • Member Avatar for JamesCherrill
    JamesCherrill

    Replied To a Post in Help Me Please

    DaniWeb Member Rules (which you agreed to when you signed up) include: "Do provide evidence of having done some work yourself if posting questions from school or work assignments" http://www.daniweb.com/community/rules …

The End.