More than one JFrame and disposing them - memory leaks...

Question

Hi,
I'm opening more than one JFrame from my application. The main JFrame is a standard one and each new one is a little bit different:
class MyFrame extends JFrame {
  public MyFrame() {
    setDefaultCloseOperation(DISPOSE_ON_CLOSE);
    new MyThread().start();
  private class MyThread extends Thread {
    public void run() {
}The problem is the when I use this inner thread and then close the frame, no resources are freed (of course I am sure this inner thread is no longer running and then I close the frame). Each resource is stored only locally.
I tried to add the finalize() method, run time to time System.gc() and System.runFinalization() from the main thread and that is what I observed:
- the finalize() of the MyThread class sometimes is invoked,
- the finalize() of the MyFrame class is never invoked.
When I throw away running this inner thread - finalize() of MyFrame is invoked.
Is there any general rule for creating such multithreaded solutions with swing components which I don't know? Or there must be something weird in my implementation of MyThread? One more info - when closing JFrame isAlive() of MyThread returns false (I have tested it using window listener).
milt

Answer 1

Since your inner class is non-static, it maintains an implicit reference to
the enclosing class. That would keep it from getting collected while the
thread is running. Unless closing the Frame forces the thread to
stop somehow, the thread will keep running to completion.
finalize() is not a reliable source of data, sadly.