//老的类
public class A
{
   protected C c
   public A(C c)
   {
      this.c=c;
   }

   public void dosome()
  {
     //do some 1
     //do some 2
  }
}


Public class B extends A
{
    private A a ;
    public B(C c)
    {
         super(c);
         a =new A(c);
     }

     public void dosome()
     {
            //do some c;
            //do some d;
     }
}