code: public static <T> T checkNotEmpty(T reference, @Nullable Object errorMessage) {
          checkNotEmpty(reference, String.valueOf(errorMessage), EMPTY_ERROR_MESSAGE_ARGS);
          return reference;
      }
docs: Performs emptiness and nullness check.
  
  @param reference    reference to check
  @param errorMessage the exception message to use if the check fails; will
  be converted to a string using {@link String#valueOf(Object)}
  @param <T>          the reference type
  @return the checked reference
  @throws IllegalArgumentException if the {@code reference} is empty
  @throws NullPointerException     if the {@code reference} is null
  @see #checkNotEmpty(Object, String, Object...)