接口的小应用

package cn.exp;//编译看左边，执行看右边//所以：TestInterface demo=new TestInterface();要是写成//InterfaceDemo demo=new TestInterface();在demo.out()会报错//因为在编译的时候要检查InterfaceDemo接口中是否有out()方法interface InterfaceDemo{public void show();}public class TestInterface implements InterfaceDemo{@Overridepublic void show() {}public void out(){System.out.println("out");}public static void main(String[] args) {TestInterface demo=new TestInterface();demo.out();}      }