Thread.suspend and Thread.resume

Question

I'm trying to build a class to replace the use of Thread.suspend() and Thread.resume() deprecated methods.
I tried to as recommended on sun web page but it doesn't work : illegate state monitor exception.
Does anyone have a solution ?
Note :
Source code
package com.utils;
public class SuspendableThread extends Thread {
     private Object mutex = new Object() ;
     private volatile boolean suspended = false ;
     private Runnable runnable ;
     public SuspendableThread ( Runnable runnable )
          super(runnable) ;
          this.runnable = runnable ;
     * Suspend the current thread
     public void doSuspend()
          synchronized (mutex) {
               suspended = true ;
               while(suspended) {
                    try {
                         runnable.wait() ;
                    } catch (InterruptedException e) {
                         e.printStackTrace();
     * Resume the current thread if suspended
     public void doResume()
          synchronized (mutex) {
               if (suspended) {
                    suspended = false ;
                    runnable.notify() ;
Exception
java.lang.IllegalMonitorStateException: current thread not owner
     at java.lang.Object.wait(Native Method)
     at java.lang.Object.wait(Unknown Source)
     at com.utils.SuspendableThread.doSuspend(SuspendableThread.java:39)

Answer 1

If you're synchronizing on the mutex, you should wait() and notify() on the mutex.
synchronized (mutex) {
    suspended = true ;
    while(suspended) {
        try {
            mutex.wait(); //wait on the mutex
        } catch (InterruptedException e) {
            e.printStackTrace();
synchronized (mutex) {
    if (suspended) {
       suspended = false ;
        mutex.notify(); //notify threads waiting on the mutex
//...