static synchronize

[Atul Shukla]

Hi! ranchers
i have a little question-
if i synchronize static block on instance it runs fine, but is that different from getting lock of "Class" object as static methods holds by default for eg:
class a{
static void o() {

synchronized(new a()){ // 1
}

}

}
i mean to say am i getting lock on class represented by newly created instance at line 1.

Thanks in advance!

[Henry Wong]

i mean to say am i getting lock on class represented by newly created instance at line 1.

You are synchronizing with the instance of class A that you created at line #1. And since, it is impossible for any other thread to get access to that lock -- you don't save a reference to the object anywhere -- it pretty much doesn't do anything useful.

Henry

[Henry Wong]

To give a further example of locking with the "Class" object, and synchronization of static methods... All three of these methods are synchronizing on the same lock...

  public class SyncStatic {
      public static synchronized void testMethodOne() {
          // Blah, Blah, Blah
      }
 
      public static void testMethodTwo() {
          synchronized (SyncStatic.class) {
              // Yada, yada, yada
          }
      }
 
      public void testMethodThree() {
          synchronized (this.getClass()) {
              // Bada bing, bada boom
          }
      }
  }

Henry

[Atul Shukla]

Thank you Henry