ServletContextImpl.java 文件源码

@Override
public <T extends EventListener> void addListener(final T t) {
    ensureNotInitialized();
    ensureNotProgramaticListener();
    if (ApplicationListeners.listenerState() != NO_LISTENER &&
            ServletContextListener.class.isAssignableFrom(t.getClass())) {
        throw UndertowServletMessages.MESSAGES.cannotAddServletContextListener();
    }
    ListenerInfo listener = new ListenerInfo(t.getClass(), new ImmediateInstanceFactory<EventListener>(t));
    deploymentInfo.addListener(listener);
    deployment.getApplicationListeners().addListener(new ManagedListener(listener, true));
}