I do the following test with the subclass JMXMPConnector:

  // create a connector server (but do not start it)
  connectorServer = new JMXMPConnectorServer(address, null, mbs);

  // create a connector client
  connector = new JMXMPConnector(address, null);

  // try to connect the client to the server
  // An IOExcpetion is expected
  try {
    connector.connect();
  }
  catch (IOException e) {
     ref.println("(OK) Expected IOException raised");
  }

  // close the connector client
  connector.close();

I receive a NullPointerException:
java.lang.NullPointerException
at javax.management.remote.generic.GenericConnector.close(GenericConnector.java:292)
at javax.management.remote.generic.GenericConnector.close(GenericConnector.java:225)
at tests.api.javax.management.remote.generic.GenericConnector.GenericConnectorTest.cleanTest(GenericConnectorTest.java:376)
at tests.api.javax.management.remote.generic.GenericConnector.GenericConnectorTest.ConnectorConnect002(GenericConnectorTest.java:288)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at com.sun.javatest.lib.TestCases.invokeTestCases(TestCases.java:176)
at com.sun.javatest.lib.MultiTest.run(MultiTest.java:115)
at tests.api.javax.management.remote.generic.GenericConnector.GenericConnectorTest.main(GenericConnectorTest.java:428)

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