Proxool 注册shutdown hook的代码

通过API取得当前Runtime环境， 反射调用Runtime的addShutdownhook方法。感觉为什么不直接调用却用反射，用意何在 ? ? ? ? ??

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        Thread t = new Thread(this);        t.setName("ShutdownHook");        Runtime runtime = Runtime.getRuntime();            Method addShutdownHookMethod = Runtime.class.getMethod("addShutdownHook", new Class[] {Thread.class});            addShutdownHookMethod.invoke(runtime, new Object[] {t});            ProxoolFacade.setShutdownHook(t);

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