java - Behaviour of threads with combination of synchronized methods in a class -

case 1

i have 2 synchronized methods shown below:

class {     public void synchronized methoda() {}     public void synchronized methodb() {} } 

a: have threads t1 , t2. can threads simultaneously executemethoda , methodb (respectively) belonging same instance of class a?

• my analysis: answer no because 1 method executed thread t1 , thread t2 blocked until t1 finishes execution.

b: have threads t1 , t2. can threads simultaneously execute methoda , methodb (respectively) belonging different instances of class a?

• my analysis: answer yes because t1 , t2 can execute methoda , methodb belonging different instances of class , not blocked.

is understanding correct per analysis case 1?

update: case 2

i have 2 synchronized methods, 1 non static , other static.

class {             public void synchronized methoda() {}         public void static synchronized methodb() {}     }        

a: have threads t1 , t2. can threads simultaneously execute methoda , methodb (respectively) belonging same instance of class a?

• my analysis: answer no because 1 method executed t1 , t2 blocked until t1 finishes execution.

b: have threads t1 , t2. can threads simultaneously execute methoda , methodb (respectively) belonging different instances of class a?

• my analysis: answer yes because t1 , t2 can execute methoda , methodb belonging different instances , not blocked.

is understanding correct per analysis case 2?

case a: no

case b: yes

your analysis correct. synchronized keyword on instance method functionally equivalent this:

public void somemethod() {    synchronized(this) {       //code    } } 

since this different in 2 contexts, not mutually exclusive. note same method called @ same time 2 different instances.

edit

for case 2, incorrect on 2a; doesn't make sense. static synchronized method not "belong" instance of class; if did wouldn't static! doesn't synchronize on any instance of class (it has no reference instance synchronize on!) instead synchronizes on class object of a. static synchronized method in class a equivalent this:

public static void methodb() {    synchronized (a.class) {       //code    } } 

your instance method synchronize on instance i've shown above, 2 threads can run in parallel.

in case b then, can run in parallel you're still missing fundamental concept static method not associated any instance.