java - java的“冗余”包装类？

我的术语可能错了，但是有人可以解释为什么我们需要将main method包装在一个类中吗？对我来说似乎有点多余。然后，您可以再次扩展该类并添加main吗？

package bears;

import bears.Bear;

// what's the point of this Class here?
public class MakeBear {

    public static void main(String[] args)
    {
        int age;
        String name;
        Bear MyBear = new Bear("Jim", "brown", 12, 50); // constructor

        age = MyBear.getAge();
        name = MyBear.getName();

        System.out.println("The bear is called" + name +
                              " and is " + age + " years old!");
    }

另外，上述方法是否可以构成程序的结构，即在Bear方法中调用main类的构造函数，并像这样重新声明变量？

刚开始，所以对我来说有点陌生。

如果相关的话，属于我的Bear课程的一部分：

public class Bear {
    private String name;
    private String colour;
    private int age;
    private int weight;

    public Bear(String bearName, String bearColour, int bearAge, int bearWeight)
    {
        name = bearName;
        colour = bearColour;
        age = bearAge;
        weight = bearWeight;
    }
      // get/set methods

谢谢

最佳答案

main必须在一个类中，因为Java中的所有内容都是一个类。

在您的简单示例中，主要功能通常在Bear类中。 MakeBear类是不必要的。

它将被这样重写。

public class Bear {
    private String name;
    private String colour;
    private int age;
    private int weight;

    public Bear(String bearName, String bearColour, int bearAge, int bearWeight)
    {
        name = bearName;
        colour = bearColour;
        age = bearAge;
        weight = bearWeight;
    }

    public static void main(String[] args)
    {
        Bear myBear = new Bear("Jim", "brown", 12, 50); // constructor
        System.out.println("The bear is called" + myBear.getName() +
                              " and is " + myBear.getAge() + " years old!");
    }
}