What does 'synchronized' mean?

Question

I have some questions regarding the usage and significance of the synchronized keyword.

• What is the significance of the synchronized

Answer 1

volatile[About] => synchronized

synchronized block in Java is a monitor in multithreading. synchronized block with the same object/class can be executed by only single thread, all others are waiting. It can help with race condition situation when several threads try to update the same variable.

Java 5 extended synchronized by supporting happens-before[About]

An unlock (synchronized block or method exit) of a monitor happens-before every subsequent lock (synchronized block or method entry) of that same monitor.

The next step is java.util.concurrent