blackhole.java

多线程与并发处理是程序设计好坏优劣的重要课题

public class Blackhole {
    public static void enter(Object obj) {
        System.out.println("Step 1");
        magic(obj);
        System.out.println("Step 2");
        synchronized (obj) {
            System.out.println("Step 3 (never reached here)");  
        }
    }