java小程序。对类的练习和对继承的练习应用。-java applet. Of the class exercises and practice of application of inheritance.

有着面向对象的思想，很好的例子，很简单就能学会面向对象，轻松，易懂-With the idea of ​ ​ object-oriented, good example, you can learn very simple object-oriented, easy, easy to understand