new SecurityManager() {
          @Override
          public void checkPermission(Permission p) {
            if (readClassPathFiles.implies(p)) {
              throw new SecurityException("Disallowed: " + p);
            }
          }
        };
    System.setSecurityManager(disallowFilesSecurityManager);
    try {
      file.exists();
      fail("Did not get expected SecurityException");