public class Deadlock extends Object {
private String objID;
public Deadlock(String id) {
objID = id;
}
public synchronized void checkOther(Deadlock other) {
print("entering checkOther()");
try {
Thread.sleep(2000);
} catch (InterruptedException x) {
}
print("invoke 'other.action()'");
other.action();
print("leaving checkOther()");
}
public synchronized void action() {
print("entering action()");
// simulate some work here
try {
Thread.sleep(500);
} catch (InterruptedException x) {
}
print("leaving action()");
}
public void print(String msg) {
threadPrint("objID=" + objID + " - " + msg);
}
public static void threadPrint(String msg) {
String threadName = Thread.currentThread().getName();
System.out.println(threadName + ": " + msg);
}
public static void main(String[] args) {
final Deadlock obj1 = new Deadlock("Thread 1");
final Deadlock obj2 = new Deadlock("Thread 2");
Runnable runA = new Runnable() {
public void run() {
obj1.checkOther(obj2);
}
};
Thread thread = new Thread(runA, "A");
thread.start();
try {
Thread.sleep(200);
} catch (InterruptedException x) {
}
Runnable runB = new Runnable() {
public void run() {
obj2.checkOther(obj1);
}
};
Thread threadB = new Thread(runB, "B");
threadB.start();
try {
Thread.sleep(5000);
} catch (InterruptedException x) {
}
threadPrint("finished sleeping");
threadPrint("about to interrupt() threadA");
thread.interrupt();
try {
Thread.sleep(1000);
} catch (InterruptedException x) {
}
threadPrint("about to interrupt() threadB");
threadB.interrupt();
try {
Thread.sleep(1000);
} catch (InterruptedException x) {
}
threadPrint("did that break the deadlock?");
}
}