code: public static Class<?> primitiveEquivalentOf (Class<?> clazz)
      {
          return clazz.isPrimitive() ? clazz : _objectToPrimitiveMap.get(clazz);
      }
docs: @param clazz a Class.
  
  @return the class's primitive equivalent, if clazz is a primitive wrapper.  If clazz is
  primitive, returns clazz.  Otherwise, returns null.