synchronized

If a synchronized method calls another non-synchronized method, is there a lock on the non-synchronized method

If a synchronized method calls another non-synchronized method, is there a lock on the non-synchronized method The answer depends on the context. If you are in a synchronized method for an object, then calls by other threads to other methods of the same object instance that are also synchronized are locked. However calls by other … Read more

Learning Java, use of synchronized keyword

Two things: First, it is not possible for two invocations of synchronized methods on the same object to interleave. When one thread is executing a synchronized method for an object, all other threads that invoke synchronized methods for the same object block (suspend execution) until the first thread is done with the object. Second, when … Read more

Is synchronized inherited in Java?

No, you will always have to write synchronized. If you call the synchronized method of the super class this will of course be a synchronized call. synchronized is not part of the method signature. See http://gee.cs.oswego.edu/dl/cpj/mechanics.html for detailed description from Doug Lea, Java threading boss (or so).

What is the reason why “synchronized” is not allowed in Java 8 interface methods?

While at first it might seem obvious that one would want to support the synchronized modifier on default methods, it turns out that doing so would be dangerous, and so was prohibited. Synchronized methods are a shorthand for a method which behaves as if the entire body is enclosed in a synchronized block whose lock … Read more

Why are synchronize expensive in Java?

Maybe it’s not as bad as you think It used to be terrible (which is possibly why you read that it was “very expensive”). These memes can take a long time to die out How expensive is synchronization? Because of the rules involving cache flushing and invalidation, a synchronized block in the Java language is … Read more