考核知识点：继承、this
public class Test01 {
public static void main(String[] args) {
Father f = new Father();
Son s = new Son();
System.out.println(f.getInfo());
System.out.println(s.getInfo());
s.setInfo("尚硅谷");
System.out.println(f.getInfo());
System.out.println(s.getInfo());
}
}
class Father{
private String info = "atguigu";
public void setInfo(String info){
this.info = info;
}
public String getInfo(){
return info;
}
}
class Son extends Father{
}
第2题
考核知识点：继承、this、super
public class Test02 {
public static void main(String[] args) {
Father f = new Father();
Son s = new Son();
System.out.println(f.getInfo());
System.out.println(s.getInfo());
s.test();
System.out.println("-----------------");
s.setInfo("大硅谷");
System.out.println(f.getInfo());
System.out.println(s.getInfo());
s.test();
}
}
class Father{
private String info = "atguigu";
public void setInfo(String info){
this.info = info;
}
public String getInfo(){
return info;
}
}
class Son extends Father{
private String info = "尚硅谷";
public void test(){
System.out.println(this.getInfo());
System.out.println(super.getInfo());
}
}
第3题
考核知识点：继承、this、super、重写
public class Test03 {
public static void main(String[] args) {
Father f = new Father();
Son s = new Son();
System.out.println(f.getInfo());
System.out.println(s.getInfo());
s.test();
System.out.println("-----------------");
s.setInfo("大硅谷");
System.out.println(f.getInfo());
System.out.println(s.getInfo());
s.test();
}
}
class Father{
private String info = "atguigu";
public void setInfo(String info){
this.info = info;
}
public String getInfo(){
return info;
}
}
class Son extends Father{
private String info = "尚硅谷";
public void setInfo(String info){
this.info = info;
}
public String getInfo(){
return info;
}
public void test(){
System.out.println(this.getInfo());
System.out.println(super.getInfo());
}
}
第4题
考核知识点：属性与多态无关
package com.atguigu.test04;
public class Test04 {
public static void main(String[] args) {
A a = new B();
System.out.println(a.num);
System.out.println(((B)a).num);
System.out.println(((A)((B)a)).num);
System.out.println("-------------------");
B b = new B();
System.out.println(b.num);
System.out.println(((A)b).num);
System.out.println(((B)((A)b)).num);
}
}
class A{
int num = 1;
}
class B extends A{
int num = 2;
}
第5题
考核知识点：类初始化与实例初始化
package com.atguigu.test05;
class HelloA{
public HelloA(){
System.out.println("HelloA");
}
{
System.out.println("I'm A Class");
}
static{
System.out.println("static A");
}
}
public class HelloB extends HelloA{
public HelloB(){
System.out.println("HelloB");
}
{
System.out.println("I'm B Class");
}
static{
System.out.println("static B");
}
public static void main(String[] args) {
new HelloB();
}
}
第6题
考核知识点：实例初始化方法，属性与多态无关
package com.atguigu.test06;
public class Test06 {
public static void main(String[] args) {
Father f = new Son();
System.out.println(f.x);
}
}
class Father{
int x = 10;
public Father(){
this.print();
x = 20;
}
public void print(){
System.out.println("Father.x = " + x);
}
}
class Son extends Father{
int x = 30;
public Son(){
this.print();
x = 40;
}
public void print(){
System.out.println("Son.x = " + x);//40
}
}
第7题
考核知识点：类初始化，局部变量与类变量，自增自减
package com.atguigu.test07;
public class Test07 {
static int x, y, z;
static {
int x = 5;
x--;
}
static {
x--;
}
public static void main(String[] args) {
System.out.println("x=" + x);
z--;
method();
System.out.println("result:" + (z + y + ++z));
}
public static void method() {
y = z++ + ++z;
}
}
第8题
考核知识点：多态，重写，实例初始化过程
package com.atguigu.test08;
public class Test08 {
public static void main(String[] args) {
Base b1 = new Base();
Base b2 = new Sub();
}
}
class Base {
Base() {
method(100);
}
public void method(int i) {
System.out.println("base : " + i);
}
}
class Sub extends Base {
Sub() {
super.method(70);
}
public void method(int j) {
System.out.println("sub : " + j);
}
}
第9题
考核知识点：方法的参数传递、final关键字
package com.atguigu.test09;
public class Test09 {
public static void main(String[] args) {
Other o = new Other();
new Test09().addOne(o);
System.out.println(o.i);
}
public void addOne(final Other o){
o.i++;
}
}
class Other{
public int i;
}
