System.setProperty(JAVA_CLASS_PATH.key(), oldClassPath);
    }
  }

  private static boolean contentEquals(URL left, URL right) throws IOException {
    return Resources.asByteSource(left).contentEquals(Resources.asByteSource(right));
  }

  private static class Nested {}


  public void testNulls() throws IOException {
    new NullPointerTester().testAllPublicStaticMethods(ClassPath.class);