1. A computer controlled method for efficiently accessing a node containing a pointer to a null object in a controlled access memory area in an object-oriented programming environment with statically typed variables, said node subject to garbage collection and access by a mutator, and said method comprising steps of: (a) allocating said controlled access memory area containing said null object, said null object having an address used as said pointer; (b) disabling access to said controlled access memory area during a mutator access phase so that accesses to said null object are detected in hardware and cause an exception condition without requiring explicit software instructions to test for accesses to said null object; and (c) enabling access to said controlled access memory area during a garbage collection phase so that accesses to said null object do not cause the exception condition thereby allowing said garbage collection process to trace down pointer chains without explicitly testing for null pointer values.