@Override
      public Void call() throws Exception {
        try (Connection connection = ConnectionFactory.createConnection(util.getConfiguration())) {
          connection.getAdmin().revoke(new UserPermission(user,
            Permission.newBuilder(namespace).withActions(actions).build()));
        }
        return null;
      }
Revoke permissions on a namespace from the given user. Will wait until all active
AccessController instances have updated their permissions caches or will throw an exception
upon timeout (10 seconds).
hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/SecureTestUtil.java