[CXF-8745] MemoryLeak when using SpringBus in a spring context which has a reusable parent context

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.5.3
• Fix Version/s: 3.6.0, 4.0.1, 3.5.6, 3.4.11
• Component/s: Bus
• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Eric
• Created: 04/Aug/22 13:18
• Updated: 18/Sep/23 18:48
• Resolved: 07/Mar/23 18:22

Description

SpringBus automatically registers itself as an ApplicationListener in the SpringContext and recursively also in all its parents:

 

public void setApplicationContext(ApplicationContext applicationContext) {
        ctx = (AbstractApplicationContext)applicationContext;
        @SuppressWarnings("rawtypes")
        ApplicationListener listener = new ApplicationListener() {
            public void onApplicationEvent(ApplicationEvent event) {
                SpringBus.this.onApplicationEvent(event);
            }
        };
        ctx.addApplicationListener(listener);
        ApplicationContext ac = applicationContext.getParent();
        while (ac != null) {
            if (ac instanceof AbstractApplicationContext) {
                ((AbstractApplicationContext)ac).addApplicationListener(listener);
            }
            ac = ac.getParent();
        } 
}

This leads to a MemoryLeak when the current SpringContext is closed but the ParentContext is reused for another child context, because the ApplicationListener references the SpringBus and the SpringBus references the old ApplicationContext.

 

A very simple approach to solve this problem would be to deregister the listener in a destroy-block or to just use a WeakReference. The later is also used by spring itself when they register a listener in the parent to automatically close all related child contexts.

Issue Links

• links to: GitHub Pull Request #1077