Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space

[John]

Hi i'm creating a program that opens a file and then sends the output to the GUI. If the user wishes they can then save a copy of the output to another file.

My program seems to open files without any bother however when i try and save the output of some larger files to a text file i get this error below:

Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space

I tried a file of size 1.3mb which opened and then saved fine, however when i tried a file of 10mb the file opened but i could not save the output as i kept getting the above error.

I had a look in the java controller in the java control panel and the disk space allowed is at 1GB which is its maximum.

I'm just curious is there anything else i can do in order for this to work?

Thanks

john

[JavaPF]

Good evening John,

You need to increase your Java heap space.

If Java runs out of memory, the following error occurs:

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

This can have two reasons:

* Your Java application has a memory leak.
* Your Java application really needs a lot of memory (more than 128 MB by default!). In this case the Java heap size can be increased using the following runtime parameters:

java -Xms<initial heap size> -Xmx<maximum heap size>

Defaults are:

java -Xms32m -Xmx128m

You can set this either in the Java Control Panel or on the command line, depending on the environment you run your application.

Take a look at this link for more information:

Java How To ...: 6 Common Errors in Setting Java Heap Size

[John]

Good evening John,

java -Xms<initial heap size> -Xmx<maximum heap size>

Defaults are:

java -Xms32m -Xmx128m

You can set this either in the Java Control Panel or on the command line, depending on the environment you run your application.

Take a look at this link for more information:

Java How To ...: 6 Common Errors in Setting Java Heap Size

Hey cheers for the reply

I've tried to change it in the control panel but it's at its maximum and it doesn't seem to work either when i try to do it via the command prompt.

The program still open and saves smaller files so i guess i'll crack on with it and see if i can address this problem later.

PS Someone else told me that it's possible to increase the heap space by hard coding it into the program but they didn't know the code. I had a google but couldn't find anything so i'm not sure whether it's possible or not?

John

[JavaPF]

I've never heard of you being able to hard code the heap space but I may be wrong.

I suggest you look at how the program is coded.. It could be poor coding that is causing this. A 10mb file shouldn't really cause you to increase your heap space

[John]

I've never heard of you being able to hard code the heap space but I may be wrong.

I suggest you look at how the program is coded.. It could be poor coding that is causing this. A 10mb file shouldn't really cause you to increase your heap space

Hey i've posted my code below

Do you think there could be a problem in my coding that may be causing this?

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.regex.*; 
import javax.swing.*;
 
public class Editor
    extends JFrame
    implements ActionListener {
  public static void main(String[] s) { new Editor(  ); }
 
  private JEditorPane textPane = new JEditorPane(  );
 
  public Editor(  ) {
    super("Editor v1.0");
    addWindowListener(new WindowAdapter(  ) {
      public void windowClosing(WindowEvent e) { System.exit(0); }
    });
    Container content = getContentPane(  );
    content.add(new JScrollPane(textPane), BorderLayout.CENTER);
    JMenu menu = new JMenu("File");
    menu.add(makeMenuItem("Open"));
    menu.add(makeMenuItem("Clean"));
    menu.add(makeMenuItem("Extract"));
    menu.add(makeMenuItem("Save"));
    menu.add(makeMenuItem("Quit"));
    JMenuBar menuBar = new JMenuBar(  );
    menuBar.add(menu);
    setJMenuBar(menuBar);
    setSize(300, 300);
    setLocation(200, 200);
    setVisible(true);
  }
 
  public void actionPerformed(ActionEvent e) {
    String command = e.getActionCommand(  );
    if (command.equals("Quit")) System.exit(0);
    else if (command.equals("Open")) loadFile(  );
    else if (command.equals("Save")) saveFile(  );
  }
 
  private void loadFile (  ) {
    JFileChooser chooser = new JFileChooser(  );
    int result = chooser.showOpenDialog(this);
    if (result == JFileChooser.CANCEL_OPTION) return;
    try {
      File file = chooser.getSelectedFile(  );
      java.net.URL url = file.toURL(  );
      textPane.setPage(url);
      	}
    catch (Exception e) {
      textPane.setText("Could not load file: " + e);
    }
  }
 
  private void saveFile(  ) {
    JFileChooser chooser = new JFileChooser(  );
    int result = chooser.showSaveDialog(this);
    // Save file data...
 
    if (result == JFileChooser.CANCEL_OPTION) return; // if user click on Save button
	File file = chooser.getSelectedFile();
	try {
         BufferedWriter bw = new BufferedWriter(new FileWriter(file));
         bw.write(textPane.getText());
         bw.close();
 
      	}
    catch (Exception e) {
         JOptionPane.showMessageDialog(
            this,
            e.getMessage(),
            "File Error",
            JOptionPane.ERROR_MESSAGE
         );
    } 
  } 
 
  private JMenuItem makeMenuItem( String name ) {
    JMenuItem m = new JMenuItem( name );
    m.addActionListener( this );
    return m;
  }
}

thanks

john

[JavaPF]

Hmm.. That does actually all look OK to me.

I think we need to try to get your head space increased. Do you know how much memory your computer has?

[John]

Hmm.. That does actually all look OK to me.

I think we need to try to get your head space increased. Do you know how much memory your computer has?

I've got 1GB of RAM and the CPU usage seems to vary between 30 and 60% when the program is running

[JavaPF]

1GB of RAM is more than enough.

What happens when you type java -Xms32m -Xmx128m into a command prompt?

[JavaPF]

Do you use the Eclipse IDE John?

To set java heap size in Eclipse you have 2 options:

1. Edit eclipse-home/eclipse.ini to be something like the following and restart Eclipse.

-vmargs
-Xms64m
-Xmx256m

2. Or, you can just run eclipse command with additional options at the very end. Anything after -vmargs will be treated as JVM options and passed directly to the JVM. JVM options specified in the command line this way will always override those in eclipse.ini. For example,

eclipse -vmargs -Xms64m -Xmx256m

[John]

When i try the command: java -Xms32m -Xmx128m it comes upwith the following:

Usage: java [-options] class [args...]
           (to execute a class)
   or  java [-options] -jar jarfile [args...]
           (to execute a jar file)
 
where options include:
    -client       to select the "client" VM
    -server       to select the "server" VM
    -hotspot      is a synonym for the "client" VM  [deprecated]
                  The default VM is client.
 
    -cp <class search path of directories and zip/jar files>
    -classpath <class search path of directories and zip/jar files>
                  A ; separated list of directories, JAR archives,
                  and ZIP archives to search for class files.
    -D<name>=<value>
                  set a system property
    -verbose[:class|gc|jni]
                  enable verbose output
    -version      print product version and exit
    -version:<value>
                  require the specified version to run
    -showversion  print product version and continue
    -jre-restrict-search | -jre-no-restrict-search
                  include/exclude user private JREs in the version search
    -? -help      print this help message
    -X            print help on non-standard options
    -ea[:<packagename>...|:<classname>]
    -enableassertions[:<packagename>...|:<classname>]
                  enable assertions
    -da[:<packagename>...|:<classname>]
    -disableassertions[:<packagename>...|:<classname>]
                  disable assertions
    -esa | -enablesystemassertions
                  enable system assertions
    -dsa | -disablesystemassertions
                  disable system assertions
    -agentlib:<libname>[=<options>]
                  load native agent library <libname>, e.g. -agentlib:hprof
                    see also, -agentlib:jdwp=help and -agentlib:hprof=help
    -agentpath:<pathname>[=<options>]
                  load native agent library by full pathname
    -javaagent:<jarpath>[=<options>]
                  load Java programming language agent, see java.lang.instrument
 
    -splash:<imagepath>
                  show splash screen with specified image

The same also applies when i type in java -Xmx128m

When i try java -Xmx128m Editor i just seem to get an exception saying that no class has been found

[JavaPF]

When i try java -Xmx128m Editor i just seem to get an exception saying that no class has been found

OK, in the command prompt, navigate to the location of your Editor class, then try the command:

java -Xmx128m Editor

[John]

Emm no i use JCreater.

Think this is another problem that i may have to deal with later amongst others lol.

I mean it still saves files of a smaller size, but the sizes of .wmdb can vary.

I guess i could continue on with the rest of the program

However i'm sure i've got some other problems that i may have to pickle your brain with lol

I think java is starting to melt my head!

[JavaPF]

Did you try:

in the command prompt, navigate to the location of your Editor class, then try the command:

java -Xmx128m Editor

I'm interested to know if that works?!

I think maybe there is too much junk in the .wmdb file. Have you tried saving a .txt file in your application of a similar size?

Yes sometimes Java can be complicated but its fun though right?!

[John]

Did you try:

I'm interested to know if that works?!

I think maybe there is too much junk in the .wmdb file. Have you tried saving a .txt file in your application of a similar size?

Yes sometimes Java can be complicated but its fun though right?!

Wahoo it worked!!!!

I think i must have been navigating to the wrong directory when i was trying to execute it! I'm a complete idiot!

Thanks for that!

Right basically i've got my program to open a .wmdb file and then save it - that works!

The thing that i've noticed with the .wmdb file is that the xml tags seem to contain whitespace, e.g. < t a g > instead of <tag> which is one one of the reasons why the DOMParse wouldn't work. However i've got a program that removes the white space. I tried it on the .wmdb file but it was taking forever and had to cancel it because it was going through the whole file line by line. I tried it on a smaller file however and it works.

My problem now is once i open a file using the code that i posted earlier i want the other program to remove the whitespace from the output if that makes sense lol.

Then after that i can try the DOMParse to see if i can extract the xml

I can post the code for removing the white space or do you want me to post it in the other thread?

Sorry for the long post

John

[JavaPF]

RESULT!!! Knew we would get there in the end...

With the program that removes white space, you should make it skip all the lines that are irrelevant and only start to remove the white space once it hits the first XML tag.

When reading the file line by line, you could do something like:

if (mystring.contains("< t a g >")){
//Start remove white space code
}

You might as well start a new thread seeing as this one has been solved.

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