java隐藏函数调用失败---求教

private void removeAndDeleteGroup(WifiP2pGroup wifiP2pGroup) {
mManager.removeGroup(mChannel, null);
try {
Method getNetworkId = WifiP2pGroup.class.getDeclaredMethod("getNetworkId");
Integer networkId = (Integer) getNetworkId.invoke(wifiP2pGroup);
Method deletePersistentGroup = WifiP2pManager.class.getDeclaredMethod("deletePersistentGroup",
WifiP2pManager.Channel.class, Integer.class, WifiP2pManager.ActionListener.class);
deletePersistentGroup.invoke(mManager, mChannel, networkId, null);
} catch (NoSuchMethodException e) {
Log.e("WIFI", "Could not delete persistent group", e);
} catch (InvocationTargetException e) {
Log.e("WIFI", "Could not delete persistent group", e);
} catch (IllegalAccessException e) {
Log.e("WIFI", "Could not delete persistent group", e);
}
}
显示NoSuchMethodException

隐藏函数，是私有函数吗？
如果是，则私有函数只能在类的内部调用，不能像 Public 函数那样使用类的变量调用。

java里面有隐藏函数吗?

http://maimode.iteye.com/blog/1300109

http://blog.csdn.net/sunyujia/article/details/2501709