Thread.sleep(time) vs. robot.wait(time)

Question

I'm trying to write some GUI and integration tests using JUnit and FEST. Here is what I have:

@Before
public void setUp(){
    try{
        program.main(args);
        robot.wait(30000);    //gives IllegalMonitorStateException
        Thread.sleep(30000);  //no Exception occurs here
    } catch (Exception e){
        e.printStackTrace();
    }
}

robot and args are already initialized.

Why do I get such an exception when I call wait? Why I don't get the same exception when I call sleep?

score 4 · Accepted Answer · answered Jul 14 '11 at 14:47

You're calling Object.wait() - which is not the same as Thread.sleep(). In particular:

wait() requires that you already own the monitor on the object you call it on
wait() allows the thread to be notified (via Object.notify/notifyAll) and wake up early; Thread.sleep() would require the thread to be interrupted.

score 0 · Answer 2 · answered Jul 14 '11 at 14:47

the wait() method is used in conjunction with the notify() method to synchronize threads. It is not used to delay in a given thread for some amount of time.

You get that exception because in order to wait() on a thread, you must have taken that thread's monitor first (via some kind of synchronized block or method).

Use Thread.sleep().

score 0 · Answer 3 · answered Jul 14 '11 at 14:57

0

Maybe you are looking for

robot.delay(...);

answered Jul 14 '11 at 14:57

camickr

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I'm using [FEST](http://easytesting.org/swing/apidocs/index.html) to access the robot. Does it matter which one I use? – Jul 14 '11 at 15:23
Ah, FEST has a different [Robot](http://easytesting.org/swing/apidocs/org/fest/swing/core/Robot.html) API than java.awt.[Robot](http://download.oracle.com/javase/6/docs/api/java/awt/Robot.html) – Atreys Jul 14 '11 at 15:31

Thread.sleep(time) vs. robot.wait(time)

3 Answers3