Reproduced with EA version of "Oracle Java ME SDK 3.3" connected to EA version of "Oracle Java ME Embedded 3.3 for Raspberry Pi".

Note, that in this case we have a Java VM on remote and slow physical board connected to PC where NetBeans is started.

1. Use following snippet:
--------------------------------------------
package threads;

import javax.microedition.midlet.*;

public class IMlet extends MIDlet {
    public void startApp() {
        new NewThread().start();
        sleep(2); //1 sec
        new NewThread().start();
        sleep(2); //1 sec
        new NewThread().start();
        sleep(2); //1 sec
        new NewThread().start();
        exit();
    }
    
    public void pauseApp() {
    }
    
    public void destroyApp(boolean unconditional) {
    }

    private void exit() {
        destroyApp(true);
        notifyDestroyed();
    }
    
    private void sleep(long sec) {
        try {
            Thread.sleep(sec * 1000);
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
    }
}

class NewThread extends Thread {
    private static int nr = 0;
    private int id;

    public NewThread() {
        id = nr++;
    }
    
    public void run() {
    }
}
------------------------------------------

2. Add a new thread break point:
Stop On: Thread Start, Hit count is multiple of 2, Suspend: Breakpoint thread
3. Add another breakpoint at line 14 (exit() call).
4. Debug the application.

You may find that sometimes the application stops on NewThread.run() two times,
and sometimes - only once. 

There is no "Multiple of" feature in JDWP protocol. It is emulated with "Equal to" feature, and setting new breakpoint on handling previous one. But with this approach a number of events can be missed because:
1) VM is not stopped (recommended setting is Suspend: Breakpoint thread) and continues to produce events while NetBeans handles the event
2) JDWP protocol is asynchronous. A number of ready events can be queued or being transferred already.