testoverload.java

来自「程序练习中包括书中实例程序代码和练习中要用到的代码,是压缩文件」· Java 代码 · 共 32 行

package examples.inheritance;

class SuperOverload { 
    public String toString() {
       return "superclass";
    }
}

class SubOverload extends SuperOverload {
   public String toString() {
      return "subclass";
   }
}

public class TestOverload {
   public static void main( String[] args ) {
      SuperOverload a = new SuperOverload();
      SubOverload b = new SubOverload();

      // SubOverload.toString
      System.out.println( a.toString() );
      // SuperOverload.toString
      System.out.println( b.toString() );

      // a is a SuperOverload ref to SubOverload object
      a = b;

      // SubOverload.toString
      System.out.println( a.toString() );
   }
}