• 2022-07-24
    以下抽象类的定义中,错误的是
    A: abstract class Demo1{}
    B: abstract class Demo2{
    public abstract String fun(String a);
    }
    C: abstract class Demo3{
    public String fun(){
    return "dlvtc";
    }
    }
    D: abstract class Demo4{
    public static final String str= "dlvtc";
    abstract void fun(){}
    }