sleep Vs wait

sleep():
	It is a static method on Thread class. It makes the current thread into the
	"Not Runnable" state for specified amount of time. During this time, the thread
	keeps the lock (monitors) it has acquired.
	
wait():
	It is a non-static method on Object class. It makes the current thread into the "Not Runnable"
	state. Wait is called on a object, not a thread. Before calling wait() method, the
	object should be synchronized, means the object should be inside synchronized block.
	The call to wait() releases the acquired lock.
	
For details please see the following:
Thread Java Docs -> http://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html
Object Java Docs -> http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html