public class TestAbstract { public static void main(String[] args) { System.out.println("Hello World!"); absDemo.SayHi(); //new absDemo().SayHello();//TestAbstract.java:7: 错误: absDemo是抽象的; 无法实例化 } } abstract class absDemo { public static void SayHi() { System.out.println("Hi!"); } public void SayHello() { System.out.println("Hello"); } } /* ---------- java ---------- Hello World! Hi! Output completed (0 sec consumed) - Normal Termination */