Static and Non static Synchronized methods

[Kishore Kumar]

Hi,
CAn any one let me know, Is there any difference between static and non-static synchronized methods? If yes, what is the difference?

[abhishek pendkay]

yes static synchronized methods lock on the class and instance methods lock on the object

[Kishore Kumar]

Thanks for your reply. Then suppose there are 2 threads. Thread-1 is accessing static synchronizes method. Now can thread-2 access non-static synchronized method if thread-1 is accessing staic synchronized method.

[abhishek pendkay]

yes if Thread-1 is accessing static synchronized methods of a class then Thread-2 can access the non-static synchronized methods of that class... the point is static synchronized methods and non-static synchronized methods dont block each other

[Kelvin Chenhao Lim]

Another way of looking at it is that the "synchronized" modifier is essentially just syntactic sugar for these two constructs:

"static synchronized void foo()" is behaviorally equivalent to:

static void foo() {
  synchronized (MyClass.class) {    // where MyClass is the enclosing class's name
    ...
  }
}

"synchronized void foo()" is behaviorally equivalent to:

void foo() {
  synchronized (this) {
    ...
  }
}

[ November 05, 2007: Message edited by: Kelvin Lim ]