Thread vs Runnable

Hi,

In many UI frameworks we have some way of synchronizing a job back on the main UI thread, like:

Application.invokeLater(Runnable r);

for instance if we wanted to download an image in a background thread, and display it when it's done downloading.

Most of these frameworks want a Runnable instance - on some systems I've noticed that the Runnable instance never terminates (even though their run() method has been exited), so I started using Thread instead:

invokeLater(new Thread(..));
instead of:
invokeLater(new Runnable(...));

now I'm on yet another UI framework for a different project, that also asks for Runnable instances. As a test, I gave it a Thread instance, and while the thread does terminate, it leaks a lot of memory on every call. If I pass it a Runnable, it works perfect, no leaks.

I'm just wondering what difference is there in passing these systems:

invokeLater(new Thread() { public void run() { ... } } );

vs

invokeLater(new Runnable() { public void run() { ... } } );

I expected them to behave the same way?

Thanks

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Ok I've attached my full example. The platform is google's Android. Their docs do say to pass Runnable, and no memory leaks happen when I use Runnable, but I'm just curious as to why Thread causes the memory leak, if there's some intrinsic difference between the two. May just be a platform thing, but still curious, thanks:

public class ActivityTestLeak extends Activity {
 
  /** This is Android's version of the invokeLater() target. 
    * This is their exact usage recommendation.
    */
  private Handler mHandler = new Handler();
	
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activityd);
 
    Button btn = new Button(this);
    btn.setText("Leak me");
    btn.setOnClickListener(new OnClickListener() { 
      public void onClick(View arg0) {
        testIt();
      }
    });
 
    LinearLayout ll = (LinearLayout)findViewById(R.id.ddd);
    ll.addView(btn);
  }
    
  private void testIt() {
    new Thread() {
      public void run() {
        // Causes a memory leak on each call. If Thread is replaced with Runnable,
        // then no leak.
        mHandler.post(new Thread() { public void run() {}});
      }
    }.start();
  }
}

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Thread vs Runnable

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