code: public static @Nullable AssertionError comparisonFailure(
        @Nullable String message, @Nullable Object expected, @Nullable Object actual) {
      try {
        return newComparisonFailure(clean(message), expected, actual);
      } catch (Exception e) {
        return null;
      }
    }
docs: Creates a new instance of JUnit's {@code ComparisonFailure} only if JUnit 4+ is in the classpath.
  
  @param message  the identifying message or {@code null}.
  @param expected the expected value.
  @param actual   the actual value.
  @return the created {@code ComparisonFailure}, or {@code null} if JUnit 4+ is not in the classpath.