[Null]

Code:

import java.lang.annotation.SafeVarargs;

class AdvHWP<T> implements Serializable {
      
     private transient volatile boolean running;

     @SafeVarargs
     public static void main(final String... args){
            new Thread(){
                 public synchronized void run(){
                        this.running = true;
                 }
            }.start();
            if(T instanceof String) {
                final List<T> list = Collections.unmodifiableList(Arrays.asList("Hello World!"));
                System.out.print(list.get((byte) 0));
            } else {
                 running = false;
                 return;
            }
            System.exit((byte) 0);
     }

}

Best Hello World program that anyone could ever skid. And now, it's here, on The Bytecode Club.