d=null removes the reference to Object 1 so it also becomes eligible for gc.
Now: a, b, c, and d all have the SAME reference to the same object. Making d=null, implies you make this
reference = null.
Originally posted by Jane Griscti:
Think all four objects are eligible. <code>d=c=b=a</code> changes all the references to point to Object 1; Objects 2,3 and 4 are de-referenced. <code>d=null</code> removes the reference to Object 1 so it also becomes eligible for gc.