Java - trying to pause a thread

Question

Possible Duplicate:
Java Wait and Notify: IllegalMonitorStateException

What is the problem with

    private final Object lock; 
public synchronized void run() {
    while (numItersCompleted < maxNumIters) {
        while (guiState == GuiState.PAUSED) {
            try {
                lock.wait(); // problematic line

Throws:

java.lang.IllegalMonitorStateException
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)

This is a duplicate question. You can't `wait()` or `notify()` on an object unless you are in a `synchronized(lock)` block on it. — Gray, Jul 26 '12 at 23:23

score 0 · Accepted Answer · answered Jul 26 '12 at 23:23

You didn't synchronized around the lock.

public void run() {
    while (numItersCompleted < maxNumIters) {
        while (guiState == GuiState.PAUSED) {
            try {
                synchronized (lock) {
                    lock.wait(); // problematic line
                }

I was going to add a link, but Gary bet me to it

Java - trying to pause a thread

1 Answers1