Java 的抽象类原理与用法分析

abstract class A{  
    abstract void m1( );
    public void m2( ){
    System.out.println("A类中定义的m2方法");
    }
}
class B extends A{
    void m1( ){
     System.out.println("B类中定义的m1方法");
    }
}
public class Test{
    public static void main( String args[ ] ){
     A a = new B( );
     a.m1( );
     a.m2( );
    }
}

class SubClass implements InterfaceA{ }

class < name> [extends < superclass>]
[implements< interface> [,< interface>]* ] {
< declarations>*
}

interface MyInterface{
  String s=“MyInterface”;
  public void absM1();
}
interface SubInterface extends MyInterface{
  public void absM2();
}
public class SubAdapter implements SubInterface{
  public void absM1(){System.out.println(“absM1”);}
  public void absM2(){System.out.println(“absM2”);}
}
//实现类SubAdapter必须给出接口SubInterface以及父接口MyInterface中所有方法的实现。

public interface Runner {
public void start();
public void run();
public void stop();
}
public class Person implements Runner {
public void start() {
  // 准备工作：弯腰、蹬腿、咬牙、瞪眼       // 开跑
}
public void run() {
  // 摆动手臂
  // 维持直线方向
}
public void stop() {
  // 减速直至停止、喝水。
}
}