Java Thread sleep() method

The sleep() method of thread class is used to sleep a thread for the specified amount of time.

Syntax

public static void sleep(long milis)throws InterruptedException
public static void sleep(long milis, int nanos)throws InterruptedException

Parameter

millis: It defines the length of time to sleep in milliseconds
nanos: 0-999999 additional nanoseconds to sleep

Return

Throws

IllegalArgumentException: If the value of millis is negative or the value of nanos is not in the range 0-999999.

InterruptedException: If any thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.

Example 1

public class SleepExp1 extends Thread
{  
    public void run()
    {  
        for(int i=1;i<5;i++)
        {  
            try
            {
                Thread.sleep(500);
            }catch(InterruptedException e){System.out.println(e);}  
            System.out.println(i);  
        }  
    }  
    public static void main(String args[])
    {  
        SleepExp1 t1=new SleepExp1();  
        SleepExp1 t2=new SleepExp1();  
        t1.start();  
        t2.start();  
    }  
}

Test it Now

Output:

As you know that at a time only one thread is executed. If you sleep a thread for the specified time, the thread scheduler picks up another thread and so on.

Example 2: when sleep time is negative

public class SleepExp2 extends Thread
{  
    public void run()
    {  
        for(int i=1;i<5;i++)
        {  
            try
            {
                Thread.sleep(-500); // sleep time is negative
            }catch(InterruptedException e){System.out.println(e);}  
            System.out.println(i);  
        }  
    }  
    public static void main(String args[])
    {  
        SleepExp2 t1=new SleepExp2();  
        SleepExp2 t2=new SleepExp2();  
        t1.start();  
        t2.start();  
    }  
}

Test it Now

Output:

Exception in thread "Thread-0" Exception in thread "Thread-1" java.lang.IllegalArgumentException: timeout value is negative
	at java.lang.Thread.sleep(Native Method)
	at SleepExp2.run(SleepExp2.java:9)
java.lang.IllegalArgumentException: timeout value is negative
	at java.lang.Thread.sleep(Native Method)
	at SleepExp2.run(SleepExp2.java:9)

Next TopicMultithreading in Java

← prev next →