Question

我正在尝试学习抽象方法和抽象类，但我不明白为什么会出错。谁能帮我找到错误原因吗？

我试图检查java文件以及类和方法的拼写。但是它们看起来还不错。

// Code from filename: Person.java 
// abstract class
abstract class Person {
    public String fname = "John";
    public int age = 24;
    public abstract void study(); // abstract method 
  }

  // Subclass (inherit from Person)
  class Student extends Person {
    public int graduationYear = 2018;
    public void study() { // the body of the abstract method is provided here
      System.out.println("Studying all day long");
    }
  }
// End code from filename: Person.java

// Code from filename: MyClass.java
class MyClass {
  public static void main(String[] args) {
    // create an object of the Student class (which inherits attributes and methods from Person)
    Student myObj = new Student(); 

    System.out.println("Name: " + myObj.fname);
    System.out.println("Age: " + myObj.age);
    System.out.println("Graduation Year: " + myObj.graduationYear);
    myObj.study(); // call abstract method
  }
}

我遇到以下错误：

MyClass.java:4：错误：找不到符号学生myObj =新的Student（）; ^ ^符号：班级学生所在地：班级MyClass

Answer 1

您所有的类都具有无修饰符访问级别，这意味着它们仅对包可见。将MyClass与Person / Student放在同一包中，或将其更改为public class...。

有关详细说明，请参见此：https://www.tutorialspoint.com/java/java_modifier_types.htm

为什么在此代码中出现“找不到符号错误”？

1 个答案: