Difference between wait and sleep in Tabular form

In Multithreading, both wait() and sleep() methods are used to make a thread to sleep. The main difference between both of them is, wait() puts a thread to sleep and forces it to move to suspended state, whereas, sleep puts a thread sleep for specified milliseconds.

Difference between wait() and sleep() in Tabular form

Sleep MethodWait Method
It puts a thread to sleep for some time and makes
that thread to automatically wake up after
specified time ends		It forces a thread to sleep until notify() gets triggered
It doesn't force a thread to release its lock before completing its taskIt forces a thread to release its lock before completing its task
It is not mandatory to define it within synchronised blockIt is mandatory to define it within synchronised block
It halts a thread execution temporarilyIt halts a thread execution permanently
It is invoked on threadIt is invoked on object
A thread awakes automatically or by interrupt()A thread awakes by notify() and notifyAll()
It controls a thread's execution timeIt controls multi-thread synchronization

wait() Method

Wait method makes a thread sleep and forces it to move to suspended state.

It also causes a thread to release its acquired lock.So that, other threads can get turn in order to perform their respective jobs.
A wait method always pair with a notify method. Both together provides a way of interthread communication.

Java program to demonstrate working of wait method ?

Program:

class WaitExample extends Thread
{
 @Override
 public void run() {
 print();
 }
 synchronized void print()
 {
 System.out.println("THis is child ");
 notify();
 }
}
public class Main {
 public static void main(String[] args) {
 WaitExample thread = new WaitExample();
 thread.start();
 synchronized (thread)
 {
 System.out.println("I am in synchronised :");
 try {
 thread.wait();
 } catch (InterruptedException e) {
 e.printStackTrace();
 }
 System.out.println("I am in invoked :");
 }

Output:

anotherone

sleep() Method

Sleep method puts a thread to sleep too but for specified  milliseconds.

It allows a thread to carry out its  remaining task once provided time ends. Unlike wait(), it doesn’t order a thread to release its locks until it completes its task.

Java program to demonstrate working of sleep method ?

Program:

class ThreadExample extends Thread{
    @Override
    public void run() {
        System.out.println("Child thread is about to sleep");
        try {
            sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("I am child Thread ");
    }
}
public class Main {

    public static void main(String[] args) {
ThreadExample thread1 = new ThreadExample();
thread1.start();
        System.out.println("I am Main Thread ");
    }
}

Output

Child thread is about to sleep

 I am Main Thread
 I am child Thread

 

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