父类：

package unit4;

public class Base {
    public int publicVarofBase=1;
    private int privateVarofBase=1;
    int defaultVarofBase=1;
    protected void methodOfBase() {
        System.out.println("执行父类的方法");
    }
    
    
}


子类：

package unit4;

public class Sub extends Base{
    public void methodOfSub() {
        System.out.println("执行子类的方法");
        publicVarofBase=2;
        defaultVarofBase=2;
        privateVarofBase=2;
        methodOfBase();
    }
    public static void main() {
        Sub sub =new Sub();
        sub.publicVarofBase=3;
        sub.privateVarofBase=3;
        sub.defaultVarofBase=3;
        sub.methodOfSub();
        sub.methodOfBase();
    }
}