IllegalMonitorStateException? wait() and notify()

Can someone tell me what's the deal with wait() and notify() methods? Like how to use them properly? Right now I have two threads, one being the main program and the other should run occationally when I need it... I try to get the second to wait() and second.notify() when I want to to run but IllegalMonitorStateException... so if you know a tutorial or you can explain it me it'll be great!

Thanks!

[415 byte] By [sunnzneta] at [2007-10-1 23:33:02]