public class ClassLoading {

static {
new Thread(){
public void run() {
System.out.println(new ClassLoading());
}
}.start();

System.out.println(“Hello world”);

boolean x = true;

while(x){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

public String toString() {
return “Goodbye world”;
}

public static void main(String[] args) {

}
}

This will print “Hello world” but will never print “Goodbye world”

public class ClassLoadingThread {
static {
System.out.println(“hello”);
final ClassLoadingThread x = new ClassLoadingThread();
Runnable r = new Runnable() {
public void run() {
synchronized(x) { x.notify(); }
}
};
// If we are currently being classloaded, then we won’t make it past this line, right?
new Thread(r).start();
try { synchronized(x) { x.wait(); } }
catch (Exception ex) { throw new RuntimeException(ex); }
}
public static void main(String[] args) {
System.out.println(“world”);
}
}