File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Java in General and the fly likes Need help with Thread Sleep Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Java in General
Bookmark "Need help with Thread Sleep" Watch "Need help with Thread Sleep" New topic

Need help with Thread Sleep

bob morkos
Ranch Hand

Joined: Oct 06, 2003
Posts: 56
I get the following error, could anyone help?

java.lang.IllegalMonitorStateException: current thread not owner at java.lang.Object.wait(Native Method) at java.lang.Object.wait(

Ernest Friedman-Hill
author and iconoclast

Joined: Jul 08, 2003
Posts: 24199

In the method retrieveTransponderResult, you call wait() on the daoThread object, but you're not in a synchronized method of Thread, nor in a block synchronized on that Thread object. To call wait() or notify(), you have to hold the monitor of the object you're calling them on. This is explained in the Javadoc for those methods.

I can't resist pointing out that

return new Boolean("false").booleanValue();

is exactly equivalent in effect to

return false;

except, of course, that it's vastly more expensive computationally.

This is not an advanced Java question, but a beginner's Thread question; I'm moving this to the Threads forum.

[Jess in Action][AskingGoodQuestions]
I agree. Here's the link:
subject: Need help with Thread Sleep
jQuery in Action, 3rd edition