code: public static <T> T checkNotNull(T value, String message) {
  		if (value == null) throw new NullPointerException(message);
  		return value;
  	}
docs: Ensures that the {@code value} is not {@code null}.
  
  @param <T> Type of the parameter.
  @param value the value to test for null.
  @param message the message of the {@link NullPointerException}.
  @return the value if it is not null.
  @throws NullPointerException with the {@code message} if the value is null.