JMXConnector jmxc JMXConnectorFactory.newJMXConnector( new JMXServiceURL( "service:jmx:remote+https: //127.0.0.1" )); try { try { jmxc.connect(); } finally { jmxc.close(); } } catch (IOException e) { } On close, the XNIO threads will remains waiting but will never be reused (a second attempt to connect jmxc would create new threads). The reason for this, is that upon catching an exception in "RemotingConnector.connect()", "RemotingConnector.close()" is called but return almost immediately because the state of the connection is "UNUSED". There are two ways to fix this issue: Perform cleanup as is the connection was "OPEN" in "RemotingConnector.close()" Reuse the same XNIO threads upon a further connection and add a "dispose()" method to allow complete cleanup of the resources without the need to have a successful connection.