src/main/java/org/fest/assertions/ComparisonFailureFactory.java
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;
    }
  }
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;
    }
  }
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.