If both methods are non static, like:



public synchronized void method1 ( ){

//...

}


public synchronized void method2 ( ){

//...

}



then this means they are both synchronizing on the object, so only one thread at a time can hold the lock of the object instance.
If one thread enters method1, other threads can't enter method1 or method2, because both are 'guarded' by synchronization on the object instance.



If both are static, this works the same, except that the synchronization is done on the class level:



public static synchronized void method1 ( ){

//...

}

public static synchronized void method2 ( ){

//...

}



If however, one method is static and one method is not, like this:


public synchronized void method1 ( ){

//...

}

public static synchronized void method2 ( ){

//...

}



The access to method1 is synchrnonized on the object level, and the access to method2 on the class level. This means that if one thread enters method1, the other cannot enter method1, and must wait, but it can enter method2, because the synchronization is done on another object (the class object and not the object instance).



Hope this helps.


regards,

Gunther.

www.javacoding.net