protected void afterRealmsSet() {
        applyCacheManagerToRealms();
        applyEventBusToRealms();
    }
Sets the realms managed by this <tt>SecurityManager</tt> instance.

@param realms the realms managed by this <tt>SecurityManager</tt> instance.
@throws IllegalArgumentException if the realms collection is null or empty.
core/src/main/java/org/apache/shiro/mgt/RealmSecurityManager.java