synchronized object not locked by thread before notifyAll()

Question

I want to have a boolean to notify some sections of the system that a specific service started.

For some strange reason I\'m getting the error java.lang.Illega

Answer 1

The line

MyService.notifier = Boolean.valueOf(true);

swaps out the object you're locking on, it overwrites the variable with a reference to a new object. So the object you acquired the lock on upon entering the block is not the same one that you're calling notifyAll on. All notifyAll knows is it hasn't acquired the lock on the object it's being called on, which is the new object created after the synchronize block was entered.

All the threads need to be using the same lock. Like Ian Roberts said, the lock belongs to the object. If you overwrite the object you have a new lock.