Concurrency in Java: synchronized static methods

Question

I want to understand how locking is done on static methods in Java.

let\'s say I have the following class:

class Foo {
    private static int bar = 0         


        

Answer 1

Neither, the non-static synchronized call does not acquire a lock on the class itself. (And the static synchronized block does not lock any object instantiated from that class.)

In other words the calls f.get() (locks f) and Foo.inc() (locks the class Foo) can run concurrently. They are not "synchronized".

You could use a different pattern (singleton), or make all the methods static.