Questions from Lecture on 2/14

1. What are the differences between constructors and methods?
   
   
2. What is the differerence between null and "" ?
   
   
3. Suppose we wish to add a new method to the SimpleMug class:

   /** 
    * Empties the mug (i.e., the amount of liquid 
    * in the mug becomes 0). 
    */ 
   public void empty()
   { 
       // method body 
   } 
   

   Come up with (at least) 3 possibilities for the method body.