Java继承-访问父类和子类

class Parent {
    public int publicVar = 1;
    protected int protectedVar = 2;
    private int privateVar = 3;

    public void publicMethod() {
        System.out.println("This is a public method.");
    }

    protected void protectedMethod() {
        System.out.println("This is a protected method.");
    }

    private void privateMethod() {
        System.out.println("This is a private method.");
    }
}

class Child extends Parent {
    void accessParentMembers() {
        System.out.println(publicVar);       // 可以访问
        System.out.println(protectedVar);    // 可以访问
        // System.out.println(privateVar);     // 编译错误，无法访问私有成员
        publicMethod();                       // 可以访问
        protectedMethod();                    // 可以访问
        // privateMethod();                    // 编译错误，无法访问私有方法
    }
}

public class Main {
    public static void main(String[] args) {
        Child child = new Child();
        child.accessParentMembers();
    }
}

class Parent {
    public void display() {
        System.out.println("Parent display");
    }
}

class Child extends Parent {
    @Override
    public void display() {
        System.out.println("Child display");
    }
}