Reentrant synchronization behavior with synchronized statements

Question

I have two methods in a java class that both have a block of code that synchronize using the same object. I understand that in the JAVA synchronization scheme locks acquired by a thread are reentrant. With this can i safely say the below piece of code will not cause any issues in all cases?

public class Someclass  
{  
  private static final Object LCK_OBJ = new Object();  
  //.....

  publc void method1()  
  {  
    //some code....  
    synchronized(LCK_OBJ)  
    {  
        //some sychronized code.  
        method2(..);  
    }  
    //some more code....  
  }  

  protected static final void method2(..)  
  {  
      Someclass ref = null;  
      //some code which gets different other references of SomeClass in a loop....  
      ref.method3(..);  
  }  

  publc void method3()  
  {  
    //some code....  
    synchronized(LCK_OBJ)  
    {  
      //some sychronized code.  
    }  
    //some more code....  
  }  

}//end of class    

Answer 1

Yes, synchronized blocks are reentrant. ReentrantLock is also reentrant and if you want to code the blocks yourself, you might want to use that instead as it has more flexibiliy/functionality.

I would make sure any lock is final If a lock object cannot be final, it is almost certainly a bug (or a source of confusion)

For comparison purposes, not all locks in Java are reentrant. FileLock is not as it passes the request directly to the OS.