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Question

为什么在实现多重继承时会出错？

import java.util.*;


interface Bakery
{

    public void bake(String cake,String cream);

    public void serve();

}
interface FoodCourt

{ 
    int cost=50;

    public void items(String puffs, String drinks);

    public void buffet(int cost, String delivery);

}
class Stall implements

 Bakery,FoodCourt
{ 

    public void bake(String cake, String cream)
    {
        System.out.println("Baking A Cake");
    }
    public void serve()

    {
        System.out.println("Serving the items");
    }

    public void items(String puffs, String drinks);
    {
        System.out.println("This is Item List");
    }

    public void buffet(int cost, String delivery);

    {
        System.out.println("Buffet Starts");
    }

}
class Dcoder 

{
    public static void main(String[] args)

    {
        Stall b1=new Stall();
        b1.bake("BlackForest", "Chocolate");
        b1.serve();
        FoodCourt f1=new Stall();
        f1.items("EggPuff", "ThumsUp");
        f1.buffet(50,"COD");
    }
}`

输出：

source_file.java:25: error: missing method body, or declare abstract
    public void items(String puffs, String drinks);
                ^
source_file.java:29: error: missing method body, or declare abstract
    public void buffet(int cost, String delivery);
                ^
2 errors

Answer 1

这是Robby提到的正确代码。

  

去除这两个方法签名后的分号

import java.util.*;


interface Bakery
{

    public void bake(String cake,String cream);

    public void serve();

}
interface FoodCourt

{ 
    int cost=50;

    public void items(String puffs, String drinks);

    public void buffet(int cost, String delivery);

}
class Stall implements

 Bakery,FoodCourt
{ 

    public void bake(String cake, String cream)
    {
        System.out.println("Baking A Cake");
    }
    public void serve()

    {
        System.out.println("Serving the items");
    }

    public void items(String puffs, String drinks)
    {
        System.out.println("This is Item List");
    }

    public void buffet(int cost, String delivery)

    {
        System.out.println("Buffet Starts");
    }

}
public class Dcoder 

{
    public static void main(String[] args)

    {
        Stall b1=new Stall();
        b1.bake("BlackForest", "Chocolate");
        b1.serve();
        FoodCourt f1=new Stall();
        f1.items("EggPuff", "ThumsUp");
        f1.buffet(50,"COD");
    }
}

Answer 2

这是可执行代码

 public class Dcoder {
          public static void main(String[] args)

        {
            Stall b1=new Stall();
            b1.bake("BlackForest", "Chocolate");
            b1.serve();
            FoodCourt f1=new Stall();
            f1.items("EggPuff", "ThumsUp");
            f1.buffet(50,"COD");
        }

          interface Bakery
    {

        public void bake(String cake,String cream);

        public void serve();

    }
    interface FoodCourt

    { 
        int cost=50;

        public void items(String puffs, String drinks);

        public void buffet(int cost, String delivery);

    }

    public  static class Stall implements

     Bakery,FoodCourt
    { 

        public void bake(String cake, String cream)
        {
            System.out.println("Baking A Cake");
        }
        public void serve()

        {
            System.out.println("Serving the items");
        }

        public void items(String puffs, String drinks)
        {
            System.out.println("This is Item List");
        }

        public void buffet(int cost, String delivery)

        {
            System.out.println("Buffet Starts");
        }
    }

    }

输出：

Baking A Cake
Serving the items
This is Item List
Buffet Starts
BUILD SUCCESSFUL (total time: 0 seconds)

Answer 3

您需要删除；从实现类中，更新停顿类中的以下方法

**public void items(String puffs, String drinks) {
    System.out.println("This is Item List");
}
public void buffet(int cost, String delivery)
{
    System.out.println("Buffet Starts");
}**