Java Thread holdLock() Method with Examples

by Online Tutorials Library July 22, 2022

Java Thread holdLock() method

The holdLock() method of thread class returns true if the current thread holds the monitor lock on the specified object.

Syntax

Parameter

obj: It defines the object on which to test lock ownership

Return

It returns true if and only if the current thread holds the monitor lock on the specified object. Otherwise, it returns false.

Exception

NullPointerException: This exception throws if obj is null.

Example

  public class JavaHoldLockExp implements Runnable   {      public void run()       {          // print currently executing thread           System.out.println(“Currently executing thread is: ” + Thread.currentThread().getName());          // returns true if the current thread holds the lock on the specified object           System.out.println(“Does thread holds lock? ” + Thread.holdsLock(this));          synchronized (this)           {              System.out.println(“Does thread holds lock? ” + Thread.holdsLock(this));          }      }      public static void main(String[] args)       {          JavaHoldLockExp g1 = new JavaHoldLockExp();          // create a thread          Thread t1 = new Thread(g1);          // this will call run() function          t1.start();      }  }  

Test it Now

Output:

Currently executing thread is: Thread-0  Does thread holds lock? false  Does thread holds lock? true

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