Error thread java : problem with the function "resume 0x***" (forum sun)

Question

One problem with the function of jdb occured when I tried to use it to
pilot the processor with differents threads. In fact, I use a simple example with 2 threads.
I stop the two threads with two breakpoint, and I want to resume one or the other (with the function "resume 0x****"), the one wich I resumed stop again on the breackpoint and I decide again to resume one or the other. All of that to obtain a tree of execution.
I give you the code of the class and the code of jdb.
CLASS: (it's just a object Room with a variable degre that I increment and decrement with two threads increase and decrease)
public class Test{
     public static void main(String[] args){
          Room r = new Room();
          decrease de = new decrease(r);
          increase in = new increase(r);
          de.start();
          in.start();
class Room {
     private volatile int degre=20;
     public void more(){
     degre += 4;
     public void less(){      
     degre -= 3;
class decrease extends Thread{
private Room room;
public decrease(Room r){
          room =r;
public void run(){
try{ 
     while (!interrupted()){ 
          room.less();
catch(InterruptedException e) {}
class increase extends Thread{
private Room room;
public increase(Room r){
     room =r;
public void run(){ 
     try{ 
          while (!interrupted()){
               room.more();
catch(InterruptedException e) {}
JDB:
Initializing jdb ...
stop at Test:7Deferring breakpoint Test:7.
It will be set after the class is loaded.
runrun Test
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
>
VM Started: Set deferred breakpoint Test:7
Breakpoint hit: "thread=main", Test.main(), line=7 bci=30
7 in.start();
main[1] stop at room:16
Set breakpoint room:16
main[1] stop at room:20
Set breakpoint room:20
main[1] resume
All threads resumed.
>
Breakpoint hit: "thread=Thread-0", room.less(), line=20 bci=0
20 degre -= 3;
Thread-0[1] threads
Group system:
(java.lang.ref.Reference$ReferenceHandler)0x10d Reference Handler cond. waiting
(java.lang.ref.Finalizer$FinalizerThread)0x10c Finalizer cond. waiting
(java.lang.Thread)0x10b Signal Dispatcher running
Group main:
(decrease)0x146 Thread-0 running (at breakpoint)
(increase)0x147 Thread-1 running (at breakpoint)
(java.lang.Thread)0x148 DestroyJavaVM running
Thread-0[1] resume 0x147
Thread-0[1]
Breakpoint hit: "thread=Thread-1", room.more(), line=16 bci=0
16 degre += 4;
Thread-1[1] resume 0x147
Thread-1[1]
Breakpoint hit: "thread=Thread-1", room.more(), line=16 bci=0
16 degre += 4;
Thread-1[1] print degre
degre = 24
Thread-1[1] resume 0x146 //It's here the problem, thread 0x146 have to stop on the //next breakpoint of decrease but nothing happen
Thread-1[1] resume 0x147
Thread-1[1]
Breakpoint hit: "thread=Thread-1", room.more(), line=16 bci=0
16 degre += 4;
Thread-1[1] clear
Breakpoints set:
breakpoint Test:7
breakpoint room:16
breakpoint room:20
PS: I tried many other examples with other class and other kind of breakpoints, but, in any cases, on thread doesn't manage to resume. When I try with general resume (no specification of the thread), It works but it isn't interresting for me because I want to decide wich thread continue his execution.

Answer 1

Hi,
I have read the FAQ of the JMF.
The problem was the jar files of the JMF were not in the JRE\BIN\EXT
folder of the Java runtime!
now it works!
thanks
Reg