Java不是完美的，Java的不足除了体现在运行速度上要比传统的C++慢许多之外，Java无法直接访问到操作系统底层（如系统硬件等)，为此Java使用native方法来扩展Java程序的功能。-Java is not perfect, Java in addition to the lack of speed in the run than traditional C++ Slow many outside, Java can not directly access to the underly