code: @SuppressWarnings("unchecked")
      public static <T> T getJlsDefaultValue(Class<T> type) {
          if(!type.isPrimitive()) {
             return null;
          }
          return (T) JLS_PRIMITIVE_DEFAULT_VALUES.get(type);
      }
docs: See also JLS8, 4.12.5 Initial Values of Variables.
  
  @param type
  @return the default value for the given type as defined by JLS