When a JMS appender is stopping, it only closes its JMS connection if started equals true. See link below
https://github.com/qos-ch/logback/blob/master/logback-classic/src/main/java/ch/qos/logback/classic/net/JMSTopicAppender.java#L140
https://github.com/qos-ch/logback/blob/master/logback-classic/src/main/java/ch/qos/logback/classic/net/JMSQueueAppender.java#L140

However, in the appender start method, if anything goes wrong after the JMS connection is created (in my case, failed to lookup a topic from JNDI), then the appender, which already has a JMS connection, will not be started. When the appender stops, the JMS connection will not be closed.

A JMS connection, once created, even if not started, may have resources (e.g. thread, thread pool, socket connection) allocated to it. Therefore, if not closed correctly, will cause resource leak.

Tomcat 7.0.35
ActiveMQ 5.10.0