When SimpleMessageListenerContainer could not connect, it throws a NullPointerException in shutdown() [SPR-9930]

[spring-projects-issues]

Geert Pante opened SPR-9930 and commented

When I start a simpleMessageListenerContainer while the ActiveMQ server is down, I get:

to perform GET on: http://localhost:22012 as response was: Connection to http://localhost:22012 refused
        at org.apache.activemq.util.JMSExceptionSupport.create(JMSExceptionSupport.java:35)
        at org.apache.activemq.ActiveMQConnectionFactory.createActiveMQConnection(ActiveMQConnectionFactory.java:295)
        at org.apache.activemq.ActiveMQConnectionFactory.createActiveMQConnection(ActiveMQConnectionFactory.java:239)
        at org.apache.activemq.ActiveMQConnectionFactory.createConnection(ActiveMQConnectionFactory.java:185)
        at org.springframework.jms.support.JmsAccessor.createConnection(JmsAccessor.java:184)
        at org.springframework.jms.listener.AbstractJmsListeningContainer.createSharedConnection(AbstractJmsListeningContainer.java:403)
        at org.springframework.jms.listener.AbstractJmsListeningContainer.establishSharedConnection(AbstractJmsListeningContainer.java:371)
        at org.springframework.jms.listener.SimpleMessageListenerContainer.doInitialize(SimpleMessageListenerContainer.java:187)

        at org.springframework.jms.listener.AbstractJmsListeningContainer.initialize(AbstractJmsListeningContainer.java:193)
        ... 10 more

I can catch this exception, and the container will keep retrying, which is a good thing.

If I want to shut it down, I do

try
{
    if (jmsContainer.isRunning())
    {
        jmsContainer.stop();
    }
    jmsContainer.destroy();
    jmsContainer = null;
}
catch (JmsException e)
{
    log.warn("Exception stopping listener: ", e);
}

But here I get a NullPointerException from the destroy():

Caused by: java.lang.NullPointerException
        at org.springframework.jms.listener.SimpleMessageListenerContainer.doShutdown(SimpleMessageListenerContainer.java:325)
        at org.springframework.jms.listener.AbstractJmsListeningContainer.shutdown(AbstractJmsListeningContainer.java:231)
        at org.springframework.jms.listener.AbstractJmsListeningContainer.destroy(AbstractJmsListeningContainer.java:172)

Apparently, this.consumers and this.sessions are null, while you try to iterate over them.

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Affects: 3.0.7