java - 错误: expected nm ="Sam";

Question

import java.util.*;

public abstract class Player {
    abstract String nm;
    public abstract void displayDetails();
}

class Booking extends Player {
nm = "Sam";           

    void displayDetails() {
        System.out.println("Name is:" + nm);
    }
}

//代码产生错误:标识符预期 nm="sam";

Answer 1

在 Java 中，您应该仅将表达式保留在 block 内。您不能将 nm = "Sam"; 保留在那里，将其移至实例初始化 block 内

import java.util.*;

public abstract class Player {
    String nm; // instance fields cant be declared as abstract
    public abstract void displayDetails();
}

class Booking extends Player {
    { // instance initialization block
      nm = "Sam";
    }

    void displayDetails() {
        System.out.println("Name is:" + name);
    }
}