Question

我正在做有关Java类的练习。代码如下。

如果在嵌入式调用资源管理器之前添加静态修饰符，则可以运行代码而不会出现问题。但是，如果我不添加“静态”，则会看到以下错误：

内部类Government中的非法静态声明。Explorer修饰符“ static”仅在常量变量声明中允许。

顺便说一句，该练习来自加州大学伯克利分校的CS61B 2018年春季。提供了原始代码here：

public class Government {
    private int treasury = 5;

    public static Government greaterTreasury(Government a, Government b) {
        if (a.treasury > b.treasury) {
            return a;
        }
        return b;
    }


   public static class Explorer {
        public static void doStuff(Government a, Government b) {
            Government favorite = Government.greaterTreasury(a, b);
            System.out.println("The best government has treasury " + favorite.treasury);            
        }
    }

   public static void main(String[] args){
      Government a = new Government();
      a.treasury = 10;
      Government b = new Government();
      b.treasury = 11;
      Government.Explorer.doStuff(a, b);

   }

}

Answer 1

没有外部类的实例，就不能引用非静态内部类。

内部类不能具有静态成员（常量除外）

请参见Why can't we have static method in a (non-static) inner class?

Java嵌入式类，何时使用静态或非静态？

1 个答案: