public void destroy() {
        LifecycleUtils.destroy(getCacheManager());
        this.cacheManager = null;
        LifecycleUtils.destroy(getEventBus());
        this.eventBus = new DefaultEventBus();
    }
Destroys the {@link #getCacheManager() cacheManager} via {@link LifecycleUtils#destroy LifecycleUtils.destroy}.
core/src/main/java/org/apache/shiro/mgt/CachingSecurityManager.java