Multithreading Basics (II)

Reentrant lock

When a thread requests a lock held by another thread , The requesting thread will enter a blocking state

Because the built-in lock is reentrant , So if a thread tries to acquire a lock that is already held by itself , This request can succeed

public class ReloadDemo {
    private Object childLock = new Object();

    public void doSomething(){
        synchronized(childLock){
            System.out.println("Do something.");
            this.doSomethingAgain();
        }
    }

    public void doSomethingAgain(){
        synchronized(childLock){
            System.out.println("Child do something  .");
        }
    }

    public static void main(String[] args) {
         ReloadDemo reloadDemo = new ReloadDemo();
         reloadDemo.doSomething();
    }

}