code: public static void setPrivateField(Object obj, String fieldName, Object newValue) {
  		try {
  			FieldUtils.writeField(obj, fieldName, newValue, true);
  		}
  		catch (IllegalAccessException e) {
  			throw new RuntimeException(e);
  		}
  	}
docs: Set the {@code newValue} to private field {@code fieldName} of given object {@code obj}.
  
  @throws IllegalArgumentException
  if given field was not found