java - Synchronized block equivalent to static synchronized method? -

when have method such following:

public synchronized void addone() {     a++; } 

it equivalent following: (correct me if i'm wrong)

public void addone() {     synchronized(this) {         a++;     } } 

but equivalent following method?:

public static synchronized void addone() {     a++;     // (in case 'a' must static) } 

what synchronized block acts same static synchronized method? understand static synchronized method synchronized on class , not instance (since there no instance), syntax that?

it equivalent locking on class object. can reference class object writing class name followed .class. so, like:

synchronized(yourclass.class) { } 

see java language specification, section 8.4.3.6 synchronized methods:

a synchronized method acquires lock (§17.1) before executes. class (static) method, lock associated class object method's class used. instance method, lock associated (the object method invoked) used.