need some help understanding this code

I was just looking over this code some more (I posted about it previously; it's from a Berkeley data structures class). The code is designed to generate all permutations from 0 to n-1. I've never taken a Java class; I'm teaching myself. I have two questions about the code provided.

1. My first question has to do with this snippet:

 private void setAllPerms () {    
     final ArrayList<int[]> perms = new ArrayList<int[]> (); 
     map (new Procedure<int[]> () {      
      public void apply (int[] p) {	
        perms.add (p);      
      }    
      });    
      allPerms = perms.iterator ();  
  }

First, the final keyword is used on the perms ArrayList. Next, it appears that map modifies perms. I thought that the final keyword made its variable immutable, therefore I'm confused why perms.add(p) is allowed? There is a note that says: "The perms list in setAllPerms is 'final' in order to be used inside this anonymous subtype." But I still don't understand it because in my mind the final keyword should always mean immutable.

2. My next question is about the usage of clone() in this snippet:

  public int[] next () {    
     if (! hasNext ())       
        throw new NoSuchElementException ();    
     getNext ();    
     return last.clone ();  
  }

Why not just return last instead of returning a clone of last?

Thanks for any help!