Help I have a memory leak...

[cdman52]

I'm using some software called WireFusion to develop an interactive 3D biology page. Anyway, I have some code here that gets called every millisecond or so, and if the audio isn't currently playing it will start it based on the step the user is at in the 3D animation. The problem is that if you go through the audio enough times java will crash. I could turn the memory up a lot and then the chances of crashing go down but that doesn't solve the problem. Somewhere my objects aren't deleting.

Here's the class that's causing the problem. I think the problem is in the inport_playAudio function but maybe it's not. I think maybe the stream isn't releasing its resources when I call stream.close(), or maybe I'm not closing it correctly.

Any help would be great.

package wobs.java.player.extension;

import com.wirefusion.player.*;
import wobs.java.player.JavaWob;
import wobs.number.player.NumberWob;
import wobs.bool.player.BoolWob;
import wobs.text.player.TextWob;
import wobs.number2d.player.Number2DWob;
import wobs.color.player.ColorWob;
import java.awt.*;
import globals.*;
import javax.sound.sampled.*;
import java.io.*;
import javax.sound.sampled.AudioInputStream;

public class JavaWob118570912 extends JavaWob
{
   private boolean initialized = false;
   private String audio[];
   private boolean audioOn = false;
   private boolean playing = false;
   Clip clip;
   AudioInputStream stream;
   DataLine.Info info;
   
   public void init()
   {
      if(initialized == false)
         setup();
   }
   
   public void inport_toggleAudio(double arg)
   {
      int togVal = (int)(arg / 1);
      System.out.println("Toggle Audio: " + togVal);
      if(togVal == 1)
         audioOn = true;
      else
      {
         audioOn = false;   
         if(playing)
            clip.stop();   
      }
   }

   public void setup()
   {      
      audio = null;
      clip = null;
      stream = null;
      info = null;
      
      audio = new String[GlobalData.clips.length];
      for(int i=0; i < GlobalData.clips.length; i++)
      {
         audio[i] = GlobalData.clips[i];
      }
   }
   
   public void inport_playAudio(double arg)
   {
      int step = (int)(arg / 1)-1;
   
      if(audioOn && playing == false)
      {      
         if(clip != null && clip.isRunning())
         {
            clip.stop();
            clip = null;
         }
         
         try {
           // From file
           if(stream != null)
              stream.close();
           stream = null;
          
         stream = AudioSystem.getAudioInputStream(getResource(audio[step]).getInputStream());
        
         AudioFormat format = stream.getFormat();
         // Create the clip
        
           info = null;
           
         DataLine.Info info = new DataLine.Info(Clip.class, stream.getFormat(), ((int)stream.getFrameLength()*format.getFrameSize()));
        
         clip = (Clip) AudioSystem.getLine(info);
          
          info = null;
         // Add a listener for line events
         clip.addLineListener(new LineListener()
         {
            public void update(LineEvent evt)
           {
              if (evt.getType() == LineEvent.Type.STOP)
             {
                System.out.println("Stopped.");
                playing = false;
                
                try
                {                   
                   if(stream != null)
                          stream.close();
                       stream = null;
                    }
                    catch (IOException e)
                   {
                        System.out.println("Problem with the IO. " + e.getMessage());
                        playing = false;
                   }                    
                  }
           }
            });
          
         // This method does not return until the audio file is completely loaded
         clip.open(stream);
         // Start playing
         clip.start();
         playing = true;
       }
         catch (IOException e)
       {
            System.out.println("Problem with the IO. " + e.getMessage());
            playing = false;
       }
         catch (LineUnavailableException e)
         {
            System.out.println("Problem with the line. " + e.getMessage());
            playing = false;
       }
         catch (UnsupportedAudioFileException e)
         {
            System.out.println("Unsupported Audio. " + e.getMessage());
            playing = false;
       }      
      }
   }
   
   public void inport_stopAudio()
   {
      if(playing)
      {
         playing = false;
         clip.stop();
         clip = null;   
         
         try
         {
            if(stream != null)
              stream.close();
           stream = null;         
         }
         catch (IOException e)
       {
            System.out.println("Problem with the IO. " + e.getMessage());
            playing = false;
       }      
      }   
   }
}

[cdman52]

Bump.

Any help?

[Eranga]

Check the all streams you've used closed in the correct place. Within the code, if any of your stream is no longer use, better to close them. Later you can open them(simplicity based on your design)

Did you try to call garbage collector manually. Actually we cannot guaranteed that it'll clearup all unnecessary memory, but it will. Just give a try and see.

[Steve11235]

So do I. Oh, you mean on your computer...

Eranga is correct about closing your streams. Also, make sure you don't have circular references, where two objects refer to each other.

Two last resorts. Use a custom class loader to load the audio classes. After each "session", get rid of the class loader (I don't remember the method). This will unload all the classes it loaded from memory. Get a new class loader and reload to start the next session. If the audio classes use native objects, those objects may be the problem. In that case, at the end of each session, start a new JVM using Runtime.exec() and let the current one end. That will definitely free up resources.

[Eranga]

Actually most of time these types of errors cause because of endless loops. Those things are not handle automatically with GC.

[Steve11235]

I want to correct myself. Circular references, by themselves, don't interfere with gc.

I saw that you add listeners to the clips. Are you removing the listeners? If not, that would likely prevent the clips from getting gc'ed, even though you null'ed the reference to the clip itself.

[Eranga]

Ya that's true Steve, to use the GC need a better idea about how to use it different steps. But in this case, it wont harm at all.

[cdman52]

Thank you Steve11235!!!
I have been working on this (1 day a week) for several weeks!!
Removing the line listener was the problem. I did that and all of the sudden my memory is back!!

Thanks.

[Steve11235]

Listeners are part of the defining class that are held by class that fires events. The fact that the clip holds a reference seems to be enough to prevent gc.

[flok]

Actually most of time these types of errors cause because of endless loops. Those things are not handle automatically with GC.

So if I have a mainloop like this:

    void myMethod()
    {
         for(;;)
         {
               scene s = s.move();
               // more code
         }
    }

then the original scene (the previous s so to say) stays in memory?

[Steve11235]

I hate to pick, but... I don't like the loop post for two reasons:

1. The variable "s" will go out of scope each time around the loop. Assuming it was assigned (as presented, it would cause an uninitialized error(?). Thus, the reference is broken each time around the loop.

2. Defining the variable "s" in a loop causes it to be repeatedly allocated and deallocated, creating a lot of needless activity on the stack. Better to define "s" outside the loop and update it within the loop. The worst than can happen is that "s" will hold a reference to one object.