Java Programming/Keywords/synchronized

synchronized is a keyword.

It marks a 'critical section'. A 'critical section' is where one and only one thread is executing. So to enter into the marked code the threads are 'synchronized', only one can enter, the others have to wait. For more information see Synchronizing Threads Methods or [1].

The synchronized keyword can be used in two ways:

• Mark a method synchronized
• Create a synchronized block

Syntax to mark a method synchronized:

public synchronized void method()
{
  // Thread.currentThread() has a lock on this object. ie. a synchronized method is the same as calling {synchronized(this){..}}.
}

Syntax to mark a synchronized block:

synchronized ( <object_reference> )
{
  // Thread.currentThread() has a lock on object_reference. All other threads trying to access it will be blocked until the current thread releases the lock.
}