Week 8

Exercises on virtual machines

• Translate the following class into Java Virtual Machine bytecode by hand:

  public class Cons {
    protected Object first;
    protected Cons rest;
   
    public Cons(Object f, Cons r) 
    { super();
      first = f; rest = r;
    }
   
    public void setFirst(Object newfirst) 
    { first = newfirst; }
   
    public Object getFirst() 
    { return first; }
   
    public Cons getRest()
    { return rest; }
   
    public boolean member(Object item)
    { if (first.equals(item))
         return true;
      else if (rest==null)
         return false;
      else
         return rest.member(item);
    }
  }
  

  Can you beat joosa+ in terms of bytes required for all methods in the class? What about javac? You probably want to refer to the JVM specification.