单继承

package lianxii;

public class TestAnimals {

    public static void main(String[] args) {

        Horse b = new Horse();
        System.out.println(b.getI());
        //        Animal b = new Animal();
        //        int yy = b.getI();
        //        System.out.println(yy);
    }

}

class Animal {

    private final int i = 3;

    public int getI() {

        return i;
    }

    //    public void setI(int i) {
    //
    //        this.i = i;
    //    } 这块设置值打开，上面final去掉，结果同样是3

}

class Horse extends Animal {

    int i = 2;
}

结果：3