IllegalMonitorStateException in code

Question

class Test {

    public static void main(String[] args) {

        System.out.println(\"1.. \");
        synchronized (args) {

            System.out.println(\"2..         


        

Answer 1

From IllegalMonitorStateException documentation

Thrown to indicate that a thread has attempted to wait on an object's monitor or to notify other threads waiting on an object's monitor without owning the specified monitor

From Object#notify() documentation

A thread becomes the owner of the object's monitor in one of three ways:

• By executing a synchronized instance method of that object.
• By executing the body of a synchronized statement that synchronizes on the object.
• For objects of type Class, by executing a synchronized static method of that class.

So since thread is executing block synchronized on args object

synchronized (args) {
    //...
}

you should call args.wait() instead Thread.currentThread().wait(); .