Java Thread sleep() Method with Examples

by Online Tutorials Library July 22, 2022

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:

1  1  2  2  3  3  4  4  5  5

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)

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