merge two arraylist lists in list1 while it remain sorted

Question

In my assignment the third step is to Call the method merge to merge the two lists in list1 so that the list1 remains sorted.

I write my code but it

Answer 1

     ArrayList a = new ArrayList();
     ArrayList b = new ArrayList();
     ArrayList c = new ArrayList();

     a.add(1);
     a.add(3);
     a.add(5);
     a.add(7);
     a.add(17);
     a.add(27);
     a.add(37);

     b.add(0); 
     b.add(2);
     b.add(4);

     while( a.size() > 0 || b.size() >0){

        if( a.size() == 0 || b.size() == 0){
            c.addAll(b);
            c.addAll(a);
            break;
        }

        if(a.get(0) < b.get(0)){
            c.add(a.get(0));
            a.remove(0);
        }
        else{
            c.add(b.get(0));
            b.remove(0);
        }

    }

    System.out.println(c.toString());