CODEWITHSUNDEEP
javastaticsynchronizednon-static
user1954799
user1954799

Reputation: 69

static synchronised method vs non static synchronised method

I have a class

class Foo{

    static synchronized get(){}
    synchronized() getMore(){}
}

I have 2 objects Foo.get() and f.getMore() running in 2 different threads t1 and t2. i had a dobuts whether when thread t1 had got a lock on the class can thread t2 access the method getMore or would t2 be prevented from getting the access and the lock to the method since the class object is locked by t1.

Upvotes: 3

Views: 651

Answers (4)

NPKR
NPKR

Reputation: 5506

The synchonized static method will aquire the lock Of java.lang.Class object which is assosiated on behalf of Foo class.

The synchonized instance method will aquire the lock of Actual object.

Upvotes: 1

Narendra Pathai
Narendra Pathai

Reputation: 41985

Static Synchronized ---> Class Level Locking (Class level scope)

it is similar to

synchronized(SomeClass.class){
 //some code
}

Simple Synchronized ---> Instance level locking

Example:

class Foo{

     public static synchronized void bar(){
         //Only one thread would be able to call this at a time  
     }

     public synchronized void bazz(){
         //One thread at a time ----- If same instance of Foo
         //Multiple threads at a time ---- If different instances of Foo class
     }

}

Upvotes: 3

Brian Agnew
Brian Agnew

Reputation: 272367

The static method will synchronise on the Class object as opposed to the instance object. You have 2 locks operating on 2 different objects. In your scenario above there will be no blocking behaviour.

Upvotes: 3

Peter Lawrey
Peter Lawrey

Reputation: 533780

synchonized locks an object and a static synchronized locks the object which represents the class.

t1 and t2 can call these methods concurrently except they cannot both be in the static synchronized method unless all but one thread is wait()ing.

Note: t1 and t2 can call getMore() at the same time for different objects.

Upvotes: 1

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