code: public static <T> T checkArgNotNull(T reference, String parameterName) {
          if (reference == null) {
              throw new NullPointerException(format("Argument '%s' must not be null", parameterName));
          }
          return reference;
      }
docs: Ensures that an object reference passed as a parameter to the calling
  method is not null.
  
  @param reference    an object reference
  @param parameterName the parameter name
  @return the non-null reference that was validated
  @throws NullPointerException if {@code reference} is null