diff --git a/javase/src/main/java/com/hongyi/day10/OrderTest.java b/javase/src/main/java/com/hongyi/day10/OrderTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..82b057dfd96359d83a3fa8c23262b4281338001d
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day10/OrderTest.java
@@ -0,0 +1,23 @@
+package com.hongyi.day10;
+
+import com.hongyi.day11.Order;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 16:23
+ * @Version 1.0
+ */
+// 与Order位于不同的包
+public class OrderTest {
+    public static void main(String[] args) {
+        Order o = new Order();
+        // 'orderDefault' is not public in 'com.hongyi.day11.Order'. Cannot be accessed from outside package
+        // o.orderDefault = 1;
+        o.orderPublic = 2;
+        // o.orderPrivate = 3;
+
+        // o.methodDefault();
+        o.methodPublic();
+        // o.orderPrivate();
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day10/PersonTest.java b/javase/src/main/java/com/hongyi/day10/PersonTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..6c5f977ff064cbc4a17f4d2ebbc1ff7017a63ec8
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day10/PersonTest.java
@@ -0,0 +1,39 @@
+package com.hongyi.day10;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/16 16:30
+ * @Version 1.0
+ */
+public class PersonTest {
+    public static void main(String[] args) {
+        Person person = new Person();
+        // 调用属性和方法
+        person.name = "Mark";
+        System.out.println(person.name);
+        System.out.println(person.age);
+        person.eat();
+        person.sleep();
+        person.talk("English");
+    }
+}
+
+class Person {
+    // 属性
+    String name;
+    int age = 1;
+    boolean isMale;
+
+    // 方法
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    public void sleep() {
+        System.out.println("sleep...");
+    }
+
+    public void talk(String language) {
+        System.out.println("talk: " + language);
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day10/UserTest.java b/javase/src/main/java/com/hongyi/day10/UserTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..bd93e802a6ddc3b9824c49eda310a5ece9115268
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day10/UserTest.java
@@ -0,0 +1,33 @@
+package com.hongyi.day10;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/16 17:04
+ * @Version 1.0
+ */
+public class UserTest {
+    public static void main(String[] args) {
+        User user = new User();
+        System.out.println(user.name); // null
+        System.out.println(user.age); // 0
+        System.out.println(user.isMale); // false
+    }
+}
+
+class User {
+    // 属性或成员变量
+    String name;
+    protected int age;
+    boolean isMale;
+
+    // 方法
+    public void talk(String language) { // 形参language，也是局部变量
+        System.out.println("talking: " + language);
+    }
+
+    public void eat() {
+        // 局部变量food
+        final String food = "川菜";
+        System.out.println("eat: " + food);
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day11/AnimalTest.java b/javase/src/main/java/com/hongyi/day11/AnimalTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..f99365009caae7a970cfaf2c9903c65295cd220f
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/AnimalTest.java
@@ -0,0 +1,53 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 15:58
+ * @Version 1.0
+ */
+public class AnimalTest {
+    public static void main(String[] args) {
+        Animal animal = new Animal();
+//        animal.name = "frog";
+//        animal.age = 24;
+//        animal.legs = 4;
+//        System.out.println(animal);
+
+        // animal.setLegs(-1); // 抛出异常
+        animal.setLegs(6);
+        System.out.println(animal.getLegs()); // 6
+    }
+}
+
+class Animal {
+    private String name;
+    private int age;
+    private int legs; // 将属性legs定义为private，只能被Animal类内部访问
+
+    // 属性设置
+    public void setLegs(int l) {
+        if (l >= 0 && l % 2 ==0) {
+            legs = l;
+        } else {
+            throw new RuntimeException("输入值错误!");
+        }
+    }
+
+    // 属性获取
+    public int getLegs() {
+        return legs;
+    }
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    @Override
+    public String toString() {
+        return "Animal{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                ", legs=" + legs +
+                '}';
+    }
+}
\ No newline at end of file
diff --git a/javase/src/main/java/com/hongyi/day11/InstanceTest.java b/javase/src/main/java/com/hongyi/day11/InstanceTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..e24981f92a53d5ce527eec7c91b7934935a47e94
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/InstanceTest.java
@@ -0,0 +1,47 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 14:50
+ * @Version 1.0
+ */
+public class InstanceTest {
+    public static void main(String[] args) {
+        Phone p = new Phone();
+        System.out.println(p);
+        p.playGame();
+        p.sendMail();
+
+        // 匿名
+        new Phone().sendMail();
+        new Phone().price = 1999;
+        new Phone().showPrice(); // 0.0
+
+        // 匿名对象的使用
+        PhoneFactory mall = new PhoneFactory();
+        mall.show(new Phone());
+    }
+}
+
+class PhoneFactory {
+    public void show(Phone phone) {
+        phone.sendMail();
+        phone.playGame();
+    }
+}
+
+class Phone {
+    double price;
+
+    public void sendMail() {
+        System.out.println("send mail...");
+    }
+
+    public void playGame() {
+        System.out.println("play game...");
+    }
+
+    public void showPrice() {
+        System.out.println("price is: " + this.price);
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day11/Order.java b/javase/src/main/java/com/hongyi/day11/Order.java
new file mode 100644
index 0000000000000000000000000000000000000000..0a5a43ded6de61ff45f163c8f20446bb27e9f0ac
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/Order.java
@@ -0,0 +1,27 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 16:19
+ * @Version 1.0
+ */
+public class Order {
+    private int orderPrivate;
+    int orderDefault;
+    public int orderPublic;
+
+    // 在类内部都可以使用
+    private void methodPrivate() {
+        orderPrivate = 1;
+        orderDefault = 2;
+        orderPublic = 3;
+    }
+
+    void methodDefault() {
+
+    }
+
+    public void methodPublic() {
+
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day11/OrderTest.java b/javase/src/main/java/com/hongyi/day11/OrderTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..3a7a0ddc79386d9cfc3ec8965c96f081ba6f6f8e
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/OrderTest.java
@@ -0,0 +1,21 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 16:20
+ * @Version 1.0
+ */
+// 与Order位于同一个包
+public class OrderTest {
+    public static void main(String[] args) {
+        Order o = new Order();
+        o.orderDefault = 1;
+        o.orderPublic = 2;
+        // 'orderPrivate' has private access in 'com.hongyi.day11.Order'
+        // o.orderPrivate = 3;
+
+        o.methodDefault();
+        o.methodPublic();
+        // o.orderPrivate();
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day11/OverloadTest.java b/javase/src/main/java/com/hongyi/day11/OverloadTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..a24f13557fece226da5d7d1ac75b6d26b05c6d35
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/OverloadTest.java
@@ -0,0 +1,31 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 15:00
+ * @Version 1.0
+ */
+public class OverloadTest {
+    public static void main(String[] args) {
+        OverloadTest test = new OverloadTest();
+        test.getSum(1, 1); // 1 2
+    }
+    // 以下都是重载的实例
+    public void getSum(int i, int j) {
+        System.out.println("1");
+        System.out.println(i + j);
+    }
+
+    public void getSum(double i, double j) {
+        System.out.println("2");
+        System.out.println(i + j);
+    }
+
+    public void getSum(int i, String s) {
+        System.out.println("3");
+    }
+
+    public void getSum(String s, int i) {
+        System.out.println("4");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day11/ValueTransferTest.java b/javase/src/main/java/com/hongyi/day11/ValueTransferTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..21371bfe6d20eefbdd234db4dca85d9fd87aa330
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/ValueTransferTest.java
@@ -0,0 +1,31 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 15:13
+ * @Version 1.0
+ */
+public class ValueTransferTest {
+    public static void main(String[] args) {
+        // 基本数据类型
+        int m = 10;
+        int n = m;
+        System.out.println("m = " + m + ", n = " + n); // 10, 10
+        n = 20;
+        System.out.println("m = " + m + ", n = " + n); // 10, 20
+
+        // 引用数据类型
+        Order1 o1 = new Order1();
+        o1.id = 1001;
+
+        Order1 o2 = o1; // 赋值以后，栈中的o1和o2的地址都指向堆中同一个对象
+        System.out.println("o1.id: " + o1.id + ", o2.id: " + o2.id); // 1001 1001
+
+        o2.id = 1002;
+        System.out.println("o1.id: " + o1.id + ", o2.id: " + o2.id); // 1002 10002
+    }
+}
+
+class Order1 {
+    int id;
+}
diff --git a/javase/src/main/java/com/hongyi/day11/ValueTransferTest1.java b/javase/src/main/java/com/hongyi/day11/ValueTransferTest1.java
new file mode 100644
index 0000000000000000000000000000000000000000..4e73cf8f058812fd9b661d8f06c5d46f07f12593
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/ValueTransferTest1.java
@@ -0,0 +1,23 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 15:23
+ * @Version 1.0
+ */
+public class ValueTransferTest1 {
+    public static void main(String[] args) {
+        int m = 10;
+        int n = 20;
+        ValueTransferTest1 test = new ValueTransferTest1();
+        test.swap(m, n);
+        System.out.println("m = " + m + ", n = " + n); // 10 20
+    }
+
+    public void swap(int m, int n) {
+        int temp = m;
+        m = n;
+        n = temp;
+        System.out.println("m = " + m + ", n = " + n); // 20 10
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day11/ValueTransferTest2.java b/javase/src/main/java/com/hongyi/day11/ValueTransferTest2.java
new file mode 100644
index 0000000000000000000000000000000000000000..2fc393a817c7b2adce7f56c619e04369ad9c4e9d
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day11/ValueTransferTest2.java
@@ -0,0 +1,29 @@
+package com.hongyi.day11;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/22 15:38
+ * @Version 1.0
+ */
+public class ValueTransferTest2 {
+    public static void main(String[] args) {
+        Data data = new Data();
+        data.m = 10;
+        data.n = 20;
+        System.out.println("m = " + data.m + ", n = " + data.n); // 10 20
+        ValueTransferTest2 test = new ValueTransferTest2();
+        test.swap(data);
+        System.out.println("m = " + data.m + ", n = " + data.n); // 20 10
+    }
+
+    public void swap(Data data) {
+        int temp = data.m;
+        data.m = data.n;
+        data.n = temp;
+    }
+}
+
+class Data {
+    int m;
+    int n;
+}
diff --git a/javase/src/main/java/com/hongyi/day12/ExtendsTest.java b/javase/src/main/java/com/hongyi/day12/ExtendsTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..6289d86932171e6438d5e3ba0df0d8577bcf72f4
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day12/ExtendsTest.java
@@ -0,0 +1,22 @@
+package com.hongyi.day12;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 15:53
+ * @Version 1.0
+ */
+public class ExtendsTest {
+    public static void main(String[] args) {
+        People p1 = new People();
+        p1.setAge(24);
+        p1.setName("Mark");
+        p1.eat();
+        p1.sleep();
+
+        Student s1 = new Student();
+        s1.setAge(24); // 使用父类中的属性和方法
+        s1.setName("Hongyi");
+        s1.setMajor("Computer Science");
+        s1.learn();
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day12/People.java b/javase/src/main/java/com/hongyi/day12/People.java
new file mode 100644
index 0000000000000000000000000000000000000000..cab1e1c0ec50464b6e35e8c77231ccec93ab91b7
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day12/People.java
@@ -0,0 +1,26 @@
+package com.hongyi.day12;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 15:49
+ * @Version 1.0
+ */
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class People {
+    private String name;
+    private int age;
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    public void sleep() {
+        System.out.println("sleep...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day12/PersonTest.java b/javase/src/main/java/com/hongyi/day12/PersonTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..264b1f292eb8095821f3b298b6c569b4d79cdb21
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day12/PersonTest.java
@@ -0,0 +1,49 @@
+package com.hongyi.day12;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 15:08
+ * @Version 1.0
+ */
+public class PersonTest {
+    public static void main(String[] args) {
+        // 创建类的实例
+        Person p1 = new Person(); // No Params Constructor...
+        Person p2 = new Person("Hongyi");
+        Person p3 = new Person(24);
+        Person p4 = new Person("Mark", 24);
+    }
+}
+
+class Person {
+    private String name;
+    private int age;
+
+    // 空参构造器
+    public Person() {
+        System.out.println("No Params Constructor...");
+    }
+
+    // 多个有参构造器
+    public Person(String name) {
+        this.name = name;
+    }
+
+    public Person(int age) {
+        this.age = age;
+    }
+
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    public void learn() {
+        System.out.println("learn");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day12/PersonTest1.java b/javase/src/main/java/com/hongyi/day12/PersonTest1.java
new file mode 100644
index 0000000000000000000000000000000000000000..6e7adbbbbb86d9f321f525d7eb312a195c6d87e7
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day12/PersonTest1.java
@@ -0,0 +1,67 @@
+package com.hongyi.day12;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 15:22
+ * @Version 1.0
+ */
+public class PersonTest1 {
+    public static void main(String[] args) {
+        Person1 p1 = new Person1();
+        p1.setName("Mark");
+        System.out.println(p1.getName()); // Mark
+        p1.eat();
+    }
+}
+
+class Person1 {
+    private String name;
+    private int age;
+
+    public Person1() {
+        this.eat();
+    }
+
+    public Person1(String name) {
+        this(); // 调用空参构造器
+        this.name = name;
+    }
+
+    public Person1(String name, int age) {
+        this(name); // 调用上一个构造器
+        this.age = age;
+    }
+
+    public void setName(String name) {
+        // this理解为当前对象
+        // 形参名和属性名相同时，必须使用this
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setAge(int a) {
+        // 形参名和属性名不同，可以不使用this
+        age = a;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void eat() {
+        System.out.println("eat...");
+        // 这里的this可以省略
+        this.speak();
+    }
+
+    public void speak() {
+        System.out.println("speak...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day12/Student.java b/javase/src/main/java/com/hongyi/day12/Student.java
new file mode 100644
index 0000000000000000000000000000000000000000..5cd4896c289e4705118ff1696b6e73b7ea3d0441
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day12/Student.java
@@ -0,0 +1,21 @@
+package com.hongyi.day12;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 15:50
+ * @Version 1.0
+ */
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class Student extends People{
+    private String major; // 定义自己的属性
+
+    public void learn() { // 定义自己的方法
+        System.out.println("learn...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day13/Person.java b/javase/src/main/java/com/hongyi/day13/Person.java
new file mode 100644
index 0000000000000000000000000000000000000000..535439d168e5ea25efc876d172b41be00e5773c7
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day13/Person.java
@@ -0,0 +1,44 @@
+package com.hongyi.day13;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 16:19
+ * @Version 1.0
+ */
+public class Person {
+    private String name;
+    private int age;
+
+    public Person() {
+
+    }
+
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    public void walk(int distance) {
+        System.out.println("walk: " + distance);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day13/PersonTest.java b/javase/src/main/java/com/hongyi/day13/PersonTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..57005add41be6295464e00d15429bf8fd2231205
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day13/PersonTest.java
@@ -0,0 +1,15 @@
+package com.hongyi.day13;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 16:24
+ * @Version 1.0
+ */
+public class PersonTest {
+    public static void main(String[] args) {
+        Student s = new Student("Mark", 24, "Computer Science");
+        s.eat(); // Student eat...
+        s.walk(10);
+        s.learn();
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day13/Student.java b/javase/src/main/java/com/hongyi/day13/Student.java
new file mode 100644
index 0000000000000000000000000000000000000000..f8ff46014deccb2900325bc7e006cacd6040449d
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day13/Student.java
@@ -0,0 +1,28 @@
+package com.hongyi.day13;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/24 16:20
+ * @Version 1.0
+ */
+public class Student extends Person{
+    private String major;
+
+    public Student() {
+
+    }
+
+    public Student(String name, int age, String major) {
+        super(name, age);
+        this.major = major;
+    }
+
+    public void learn() {
+        System.out.println("learn: " + this.major);
+    }
+
+    // 对父类方法eat的重写
+    public void eat() {
+        System.out.println("Student eat...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day14/Person.java b/javase/src/main/java/com/hongyi/day14/Person.java
new file mode 100644
index 0000000000000000000000000000000000000000..00356a3e315ff5b0e246f6c56c747090d8fcfba1
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day14/Person.java
@@ -0,0 +1,39 @@
+package com.hongyi.day14;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 19:38
+ * @Version 1.0
+ */
+public class Person {
+    String name;
+    int age;
+    int id = 1001; // 身份证号
+
+    // 空参构造器
+    public Person() {
+        System.out.println("I'm everywhere...");
+    }
+
+    public Person(String name) {
+        this.name = name;
+    }
+
+    public Person(int age) {
+        this.age = age;
+    }
+
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    public void walk(int distance) {
+        System.out.println("walk: " + distance);
+    }
+
+}
diff --git a/javase/src/main/java/com/hongyi/day14/Student.java b/javase/src/main/java/com/hongyi/day14/Student.java
new file mode 100644
index 0000000000000000000000000000000000000000..940d662a83bc2c4bcd525b31ebbf3a907bcafe5d
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day14/Student.java
@@ -0,0 +1,44 @@
+package com.hongyi.day14;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 19:38
+ * @Version 1.0
+ */
+public class Student extends Person{
+    String major;
+    int id = 1002; // 学号
+
+    public Student() {
+        // super();
+    }
+
+    public Student(String major) {
+        // 默认super()会出现在子类的所有构造器的首行
+        // super();
+        this.major = major;
+    }
+
+    public Student(String name, int age, String major) {
+        // 调用父类构造器
+        super(name, age);
+        this.major = major;
+    }
+
+    @Override
+    public void eat() {
+        System.out.println("Student eat...");
+    }
+
+    public void study() {
+        System.out.println("Student study...");
+        eat(); // 调用自身重写的方法
+        super.eat(); // 调用父类的方法
+    }
+
+    public void show() {
+        System.out.println("name = " + this.name + ", " + "age = " + super.age); // 子类没有这些属性，二者没有区别
+        System.out.println(id); // 子类id
+        System.out.println(super.id); // 父类id
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day14/SuperTest.java b/javase/src/main/java/com/hongyi/day14/SuperTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..8c78f3f68c99b7e20437c367edce798b2158af7c
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day14/SuperTest.java
@@ -0,0 +1,16 @@
+package com.hongyi.day14;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 19:38
+ * @Version 1.0
+ */
+public class SuperTest {
+    public static void main(String[] args) {
+        Student s1 = new Student("Mark", 24, "Computer Science");
+        s1.show(); // name = Mark, age = 24 1002 1001
+
+        Student s2 = new Student("Computer Science"); // I'm everywhere...
+        Student s3 = new Student(); // I'm everywhere...
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day15/AnimalTest.java b/javase/src/main/java/com/hongyi/day15/AnimalTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..a1002a5b5930be8ba8bd186f6fa832e7a4ed729f
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day15/AnimalTest.java
@@ -0,0 +1,53 @@
+package com.hongyi.day15;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:55
+ * @Version 1.0
+ */
+public class AnimalTest {
+    public static void main(String[] args) {
+        AnimalTest test = new AnimalTest();
+        test.func(new Dog());
+        test.func(new Cat());
+    }
+
+    public void func(Animal animal) { // Animal animal = new Dog();
+        animal.eat();
+        animal.shout();
+    }
+}
+
+class Animal {
+    public void eat() {
+        System.out.println("Animal eat");
+    }
+
+    public void shout() {
+        System.out.println("animal shout");
+    }
+}
+
+class Dog extends Animal {
+    @Override
+    public void eat() {
+        System.out.println("Dog eat");
+    }
+
+    @Override
+    public void shout() {
+        System.out.println("Dog shout");
+    }
+}
+
+class Cat extends Animal {
+    @Override
+    public void eat() {
+        System.out.println("Cat eat");
+    }
+
+    @Override
+    public void shout() {
+        System.out.println("Cat shout");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day15/Man.java b/javase/src/main/java/com/hongyi/day15/Man.java
new file mode 100644
index 0000000000000000000000000000000000000000..b877ba1eebe4c5a142872443c0ad36b138417f2d
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day15/Man.java
@@ -0,0 +1,24 @@
+package com.hongyi.day15;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:35
+ * @Version 1.0
+ */
+public class Man extends Person{
+    boolean isSmoking;
+
+    public void earnMoney() {
+        System.out.println("Man earn money");
+    }
+
+    @Override
+    public void eat() {
+        System.out.println("Man eat...");
+    }
+
+    @Override
+    public void walk() {
+        System.out.println("Man walk...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day15/Person.java b/javase/src/main/java/com/hongyi/day15/Person.java
new file mode 100644
index 0000000000000000000000000000000000000000..7c95b501f7d35c1d0a252872f81b519a31fcd218
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day15/Person.java
@@ -0,0 +1,19 @@
+package com.hongyi.day15;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:34
+ * @Version 1.0
+ */
+public class Person {
+    String name;
+    int age;
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    public void walk() {
+        System.out.println("walk...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day15/PersonTest.java b/javase/src/main/java/com/hongyi/day15/PersonTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..c101c310573cd92e5a0b8f07e0635e723649c338
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day15/PersonTest.java
@@ -0,0 +1,27 @@
+package com.hongyi.day15;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:38
+ * @Version 1.0
+ */
+public class PersonTest {
+    public static void main(String[] args) {
+        Person p1 = new Person();
+        p1.eat(); // eat...
+
+        Man man = new Man();
+        man.eat(); // Man eat...
+        man.earnMoney(); // Man earn money
+
+        //------------------------------
+
+        // 对象的多态：父类的引用指向子类的对象
+        Person p2 = new Man();
+        Person p3 = new Woman();
+        // 多态的使用：当调用父子类同名同参数的方法时，实际执行的是子类重写父类的方法--虚拟方法调用
+        p2.eat(); // Man eat...
+        p2.walk(); // Man walk...
+        // p2.earnMoney(); 不能调用Man中特有的方法
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day15/Woman.java b/javase/src/main/java/com/hongyi/day15/Woman.java
new file mode 100644
index 0000000000000000000000000000000000000000..3f1a450f2ae68e4d179124ae585e562bc8010bca
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day15/Woman.java
@@ -0,0 +1,24 @@
+package com.hongyi.day15;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:36
+ * @Version 1.0
+ */
+public class Woman extends Person{
+    boolean isBeauty;
+
+    public void goShopping() {
+        System.out.println("Woman go shopping");
+    }
+
+    @Override
+    public void eat() {
+        System.out.println("Woman eat...");
+    }
+
+    @Override
+    public void walk() {
+        System.out.println("Woman walk...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day16/Man.java b/javase/src/main/java/com/hongyi/day16/Man.java
new file mode 100644
index 0000000000000000000000000000000000000000..d2f16f2e3b3ae57fe1b7de454ee6738e7a377dc1
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day16/Man.java
@@ -0,0 +1,24 @@
+package com.hongyi.day16;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:35
+ * @Version 1.0
+ */
+public class Man extends Person {
+    boolean isSmoking;
+
+    public void earnMoney() {
+        System.out.println("Man earn money");
+    }
+
+    @Override
+    public void eat() {
+        System.out.println("Man eat...");
+    }
+
+    @Override
+    public void walk() {
+        System.out.println("Man walk...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day16/Person.java b/javase/src/main/java/com/hongyi/day16/Person.java
new file mode 100644
index 0000000000000000000000000000000000000000..e1cf474dfd2304370c349c96533f8c416bb8001d
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day16/Person.java
@@ -0,0 +1,19 @@
+package com.hongyi.day16;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:34
+ * @Version 1.0
+ */
+public class Person {
+    String name;
+    int age;
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    public void walk() {
+        System.out.println("walk...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day16/PersonTest.java b/javase/src/main/java/com/hongyi/day16/PersonTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..d0203077de6c995a2896a454f453eaac0029807c
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day16/PersonTest.java
@@ -0,0 +1,27 @@
+package com.hongyi.day16;
+
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:38
+ * @Version 1.0
+ */
+public class PersonTest {
+    public static void main(String[] args) {
+        // 对象的多态：父类的引用指向子类的对象
+        Person p1 = new Man();
+        // 多态的使用：当调用父子类同名同参数的方法时，实际执行的是子类重写父类的方法--虚拟方法调用
+        p1.eat(); // Man eat...
+        p1.walk(); // Man walk...
+
+        // ------------------------------
+        // p2.earnMoney(); 不能调用Man中特有的方法
+        // p2.isSmoking = true; 不能调用Man中特有的属性
+        // 向下转型，使用强转时，可能出现ClassCastException异常
+        if (p1 instanceof Man) {
+            Man m1 = (Man) p1;
+            m1.isSmoking = true;
+            m1.earnMoney();
+        }
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day16/Woman.java b/javase/src/main/java/com/hongyi/day16/Woman.java
new file mode 100644
index 0000000000000000000000000000000000000000..3c88eb1fabb70a947ff1a5463779d6f189fd28fe
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day16/Woman.java
@@ -0,0 +1,24 @@
+package com.hongyi.day16;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/28 20:36
+ * @Version 1.0
+ */
+public class Woman extends Person {
+    boolean isBeauty;
+
+    public void goShopping() {
+        System.out.println("Woman go shopping");
+    }
+
+    @Override
+    public void eat() {
+        System.out.println("Woman eat...");
+    }
+
+    @Override
+    public void walk() {
+        System.out.println("Woman walk...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day17/Customer.java b/javase/src/main/java/com/hongyi/day17/Customer.java
new file mode 100644
index 0000000000000000000000000000000000000000..6c1db5cd2b6fd8c3296479e2a70abc34246900e6
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day17/Customer.java
@@ -0,0 +1,55 @@
+package com.hongyi.day17;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/29 19:48
+ * @Version 1.0
+ */
+public class Customer {
+    private String name;
+    private int age;
+
+    public Customer(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Customer customer = (Customer) o;
+
+        if (age != customer.age) return false;
+        return name.equals(customer.name);
+    }
+
+    @Override
+    public String toString() {
+        return "Customer{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                '}';
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day17/EqualsTest.java b/javase/src/main/java/com/hongyi/day17/EqualsTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..ea7346016db10d41734c55fba77c0c2b06185236
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day17/EqualsTest.java
@@ -0,0 +1,38 @@
+package com.hongyi.day17;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/29 19:38
+ * @Version 1.0
+ */
+public class EqualsTest {
+    public static void main(String[] args) {
+        // 基本数据类型比较
+        int i = 10;
+        int j = 10;
+        double d = 10.0;
+        boolean b = true;
+        char c = 10;
+        System.out.println(i == j); // true
+        System.out.println(i == d); // true
+        System.out.println(i == c); // true
+        // System.out.println(b == i); // 编译出错
+        char c1 = 'A';
+        char c2 = 65;
+        System.out.println(c1 == c2); // true
+
+        // 引用数据类型比较
+        Customer customer1 = new Customer("Mark", 24);
+        Customer customer2 = new Customer("Mark", 24);
+        System.out.println(customer1 == customer2); // false
+
+        String str1 = new String("Hongyi");
+        String str2 = new String("Hongyi");
+        System.out.println(str1 == str2); // false
+
+        System.out.println(customer1.equals(customer2)); // false
+        System.out.println(str1.equals(str2)); // true，String类重写了equals方法，只比较字符串内容
+
+
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day17/ToStringTest.java b/javase/src/main/java/com/hongyi/day17/ToStringTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..c54e1d1b62a9f83c2147ffd409bd8330f73c9e2a
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day17/ToStringTest.java
@@ -0,0 +1,16 @@
+package com.hongyi.day17;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/29 20:15
+ * @Version 1.0
+ */
+public class ToStringTest {
+    public static void main(String[] args) {
+        Customer c1 = new Customer("Tom", 24);
+        System.out.println(c1); // com.hongyi.day17.Customer@5594a1b5
+
+        String str = new String("Hello World");
+        System.out.println(str);
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day18/MainDemo.java b/javase/src/main/java/com/hongyi/day18/MainDemo.java
new file mode 100644
index 0000000000000000000000000000000000000000..244e024d0d2db9e5e56598dcb47117c229c05300
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day18/MainDemo.java
@@ -0,0 +1,14 @@
+package com.hongyi.day18;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/30 23:01
+ * @Version 1.0
+ */
+public class MainDemo {
+    public static void main(String[] args) {
+        for (String arg : args) {
+            System.out.println(arg);
+        }
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day18/MainTest.java b/javase/src/main/java/com/hongyi/day18/MainTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..5abb35e0b8e1d360c6cb4a96f7d4b5966f57dc14
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day18/MainTest.java
@@ -0,0 +1,20 @@
+package com.hongyi.day18;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/30 22:47
+ * @Version 1.0
+ */
+public class MainTest {
+
+    public static void main(String[] args) { // 程序的入口
+        // show(); 报错，因为show不是静态方法
+        // 通过类的实例来调非静态方法
+        MainTest test = new MainTest();
+        test.show();
+    }
+
+    public void show() {
+        System.out.println("show...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day18/SingletonTest1.java b/javase/src/main/java/com/hongyi/day18/SingletonTest1.java
new file mode 100644
index 0000000000000000000000000000000000000000..7978522af93dc7ae83322eb963b9e9b05b1d6d49
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day18/SingletonTest1.java
@@ -0,0 +1,31 @@
+package com.hongyi.day18;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/30 11:11
+ * @Version 1.0
+ */
+public class SingletonTest1 {
+    public static void main(String[] args) {
+        Bank bank1 = Bank.getInstance();
+        Bank bank2 = Bank.getInstance();
+        System.out.println(bank1 == bank2); // true
+
+    }
+}
+
+// 饿汉式
+class Bank {
+    // 2.内部创建类的对象
+    private static final Bank instance = new Bank();
+
+    // 1.私有化构造器
+    private Bank() {
+
+    }
+
+    // 3.提供公共的方法返回类的对象
+    public static Bank getInstance() {
+        return instance;
+    }
+}
\ No newline at end of file
diff --git a/javase/src/main/java/com/hongyi/day18/SingletonTest2.java b/javase/src/main/java/com/hongyi/day18/SingletonTest2.java
new file mode 100644
index 0000000000000000000000000000000000000000..1fd3ac9ae5c2e0e6f69758e76f09d52eedc7a6f1
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day18/SingletonTest2.java
@@ -0,0 +1,32 @@
+package com.hongyi.day18;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/30 11:16
+ * @Version 1.0
+ */
+public class SingletonTest2 {
+    public static void main(String[] args) {
+        Order order1 = Order.getInstance();
+        Order order2 = Order.getInstance();
+        System.out.println(order1 == order2); // true
+    }
+}
+
+class Order {
+    // 1.私有化构造器
+    private Order() {
+
+    }
+
+    // 2.声明当前类对象，没有初始化
+    private static Order instance = null;
+
+    // 3.返回该对象
+    public static Order getInstance() {
+        if (instance == null) {
+            instance = new Order();
+        }
+        return instance;
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day18/StaticTest.java b/javase/src/main/java/com/hongyi/day18/StaticTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..2732ee6e0da9498686c7a96f6c3b48d7b70fb583
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day18/StaticTest.java
@@ -0,0 +1,33 @@
+package com.hongyi.day18;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/30 10:33
+ * @Version 1.0
+ */
+public class StaticTest {
+    public static void main(String[] args) {
+        Chinese.show();
+    }
+}
+
+// 中国人
+class Chinese {
+    String name;
+    int age;
+    // 类变量
+    static String nation;
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    // 静态方法
+    public static void show() {
+        // this.age = 24; 非法
+        // eat(); 非法
+        System.out.println(nation);
+        System.out.println("show...");
+    }
+}
+
diff --git a/javase/src/main/java/com/hongyi/day19/BlockTest.java b/javase/src/main/java/com/hongyi/day19/BlockTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..5ded9d10656313f6fe5289394c1614988e33c067
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day19/BlockTest.java
@@ -0,0 +1,74 @@
+package com.hongyi.day19;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 9:16
+ * @Version 1.0
+ */
+public class BlockTest {
+    public static void main(String[] args) {
+        System.out.println(Person.desc);
+
+        Person p1 = new Person();
+        System.out.println(p1);
+    }
+}
+
+class Person {
+    String name;
+    int age;
+    static String desc = "I'm a human";
+
+    public Person() {
+
+    }
+
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    // 静态代码块
+    static {
+        System.out.println("static block-1...");
+        desc = "I'm a human..."; // 重新对desc赋值
+    }
+
+    static {
+        System.out.println("static block-2...");
+        // 只能调用静态方法
+        info();
+    }
+
+    // 非静态代码块
+    {
+        // 创建对象时可以初始化属性
+        this.name = "Mark";
+        this.age = 24;
+        System.out.println("nonstatic block...");
+    }
+
+    {
+        System.out.println("nonstatic block-2...");
+        // 调用静态方法
+        info();
+        // 调用非静态方法
+        eat();
+    }
+
+    public void eat() {
+        System.out.println("eat...");
+    }
+
+    @Override
+    public String toString() {
+        return "Person{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                '}';
+    }
+
+    public static void info() {
+        System.out.println("info...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day19/FinalTest.java b/javase/src/main/java/com/hongyi/day19/FinalTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..02262314140b91cea97787baddb2f0b857bc649b
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day19/FinalTest.java
@@ -0,0 +1,25 @@
+package com.hongyi.day19;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 9:38
+ * @Version 1.0
+ */
+public class FinalTest {
+    public static void main(String[] args) {
+
+    }
+}
+
+class A {
+    public final void show() {
+
+    }
+}
+
+class B extends A {
+    // 不能重写final方法
+//    public void show() {
+//
+//    }
+}
\ No newline at end of file
diff --git a/javase/src/main/java/com/hongyi/day19/FinalTest1.java b/javase/src/main/java/com/hongyi/day19/FinalTest1.java
new file mode 100644
index 0000000000000000000000000000000000000000..f43741d0e10c6d50d9e384f39ee95cbdbc44558f
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day19/FinalTest1.java
@@ -0,0 +1,29 @@
+package com.hongyi.day19;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 9:44
+ * @Version 1.0
+ */
+public class FinalTest1 {
+
+    final int WIDTH = 10; // 显式初始化
+    final int LEFT;
+    final int RIGHT;
+
+    public FinalTest1() {
+        RIGHT = 10; // 构造器初始化
+    }
+
+    public void doWidth() {
+        // WIDTH = 20; 报错，不能修改final修饰的变量
+    }
+
+    {
+        LEFT = 10; // 代码块初始化
+    }
+
+    public static void main(String[] args) {
+
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day19/FinalTest2.java b/javase/src/main/java/com/hongyi/day19/FinalTest2.java
new file mode 100644
index 0000000000000000000000000000000000000000..a60a3faf3806d166208a51171dd9101b955e4a0b
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day19/FinalTest2.java
@@ -0,0 +1,24 @@
+package com.hongyi.day19;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 9:54
+ * @Version 1.0
+ */
+public class FinalTest2 {
+
+    public void show() {
+        final int NUM = 10; // 修饰常量
+        // NUM += 10; 编译不通过
+    }
+
+    public void show(final int num) { // 修饰形参
+        // num += 10; 编译不用过
+        System.out.println(num);
+    }
+
+    public static void main(String[] args) {
+        FinalTest2 test = new FinalTest2();
+        test.show(10);
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day20/AbstractTest.java b/javase/src/main/java/com/hongyi/day20/AbstractTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..d595a4d2d5896d93ac67db17fa3247f5005757e2
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day20/AbstractTest.java
@@ -0,0 +1,27 @@
+package com.hongyi.day20;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 10:07
+ * @Version 1.0
+ */
+public class AbstractTest {
+    public static void main(String[] args) {
+        Student s = new Student();
+        s.eat();
+    }
+}
+
+// 抽象类
+abstract class Person {
+    // 抽象方法
+    public abstract void eat();
+}
+
+class Student extends Person {
+
+    @Override
+    public void eat() {
+        System.out.println("Student eat...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day20/HumanTest.java b/javase/src/main/java/com/hongyi/day20/HumanTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..784a0de6ef95a10c246cd6f6799dbb846c696bd0
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day20/HumanTest.java
@@ -0,0 +1,37 @@
+package com.hongyi.day20;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 10:24
+ * @Version 1.0
+ */
+public class HumanTest {
+    public static void main(String[] args) {
+        // 抽象类的匿名子类对象human
+        Human human = new Human() {
+            // 对抽象方法的重写
+            @Override
+            public void eat() {
+                System.out.println("eat");
+            }
+
+            @Override
+            public void breath() {
+                System.out.println("breath...");
+            }
+        };
+
+        human.eat();
+        human.breath();
+    }
+}
+
+// 抽象类
+abstract class Human {
+
+    abstract public void eat();
+
+    abstract public void breath();
+}
+
+
diff --git a/javase/src/main/java/com/hongyi/day20/TemplateTest.java b/javase/src/main/java/com/hongyi/day20/TemplateTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..b0df02716b75d3423ea38749c4a83acc4e67f29f
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day20/TemplateTest.java
@@ -0,0 +1,46 @@
+package com.hongyi.day20;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 10:38
+ * @Version 1.0
+ */
+public class TemplateTest {
+    public static void main(String[] args) {
+        Template t = new SubTemplate();
+        t.spendTime();
+    }
+}
+
+abstract class Template {
+    // 计算某段代码所花费的时间
+    public void spendTime() {
+        long start = System.currentTimeMillis();
+        code(); // 不确定的部分
+        long end = System.currentTimeMillis();
+        System.out.println("花费的时间为: " + (end - start));
+
+    }
+
+    public abstract void code();
+}
+
+class SubTemplate extends Template {
+
+    // 找1000以内的质数
+    @Override
+    public void code() {
+        for (int i = 2; i < 1000; i++) {
+            boolean flag = true;
+            for (int j = 2; j <= Math.sqrt(i); j++) {
+                if (i % j == 0) {
+                    flag = false;
+                    break;
+                }
+            }
+            if (flag) {
+                System.out.println(i);
+            }
+        }
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day21/InterfaceTest.java b/javase/src/main/java/com/hongyi/day21/InterfaceTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..445be560d72283cd3169aa19c8f3d8a0cf63e878
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day21/InterfaceTest.java
@@ -0,0 +1,50 @@
+package com.hongyi.day21;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/1 16:58
+ * @Version 1.0
+ */
+public class InterfaceTest {
+    public static void main(String[] args) {
+        System.out.println(Flyable.MAX_SPEED);
+        System.out.println(Flyable.MIN_SPEED);
+
+        Plane plane = new Plane();
+        plane.fly();
+        plane.stop();
+    }
+}
+
+interface Attack {
+    void attack();
+}
+
+interface Flyable {
+    // 全局常量
+    int MAX_SPEED = 7000;
+    int MIN_SPEED = 1;
+
+    // 抽象方法
+    void fly();
+    void stop();
+}
+
+// 先extends后implements
+class Plane extends Object implements Flyable, Attack {
+
+    @Override
+    public void fly() {
+        System.out.println("Plane fly...");
+    }
+
+    @Override
+    public void stop() {
+        System.out.println("Plane stop...");
+    }
+
+    @Override
+    public void attack() {
+        System.out.println("Plane attack...");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day22/CompareA.java b/javase/src/main/java/com/hongyi/day22/CompareA.java
new file mode 100644
index 0000000000000000000000000000000000000000..bcaaa6e530ae4e3fa57eba26d5759ad6ac33f053
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day22/CompareA.java
@@ -0,0 +1,21 @@
+package com.hongyi.day22;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/15 16:13
+ * @Version 1.0
+ */
+public interface CompareA {
+    static void method1() {
+        System.out.println("CompareA:static method");
+    }
+
+    // 默认方法
+    default void method2() {
+        System.out.println("CompareA:default method");
+    }
+
+    default void method3() {
+        System.out.println("CompareA:default method");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day22/NetworkTest.java b/javase/src/main/java/com/hongyi/day22/NetworkTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..1bf4d0155fa81e602773ad1a3d4fc8f344ae7b22
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day22/NetworkTest.java
@@ -0,0 +1,48 @@
+package com.hongyi.day22;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/15 16:04
+ * @Version 1.0
+ */
+public class NetworkTest {
+    public static void main(String[] args) {
+        Server server = new Server();
+        ProxyServer proxyServer = new ProxyServer(server);
+        proxyServer.browse();
+    }
+}
+
+interface Network {
+    public void browse();
+}
+
+// 被代理类
+class Server implements Network {
+
+    @Override
+    public void browse() {
+        System.out.println("真实的服务器访问网络");
+    }
+}
+
+// 代理类
+class ProxyServer implements Network {
+
+    private Network network;
+
+    public ProxyServer(Network network) {
+        this.network = network;
+    }
+
+    public void check() {
+        System.out.println("联网前的检查工作");
+    }
+
+    @Override
+    public void browse() {
+        check();
+        network.browse();
+    }
+}
+
diff --git a/javase/src/main/java/com/hongyi/day22/SubClassTest.java b/javase/src/main/java/com/hongyi/day22/SubClassTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..f85069da51be758dd5c82c6cb18510bff1e32207
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day22/SubClassTest.java
@@ -0,0 +1,25 @@
+package com.hongyi.day22;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/15 16:15
+ * @Version 1.0
+ */
+public class SubClassTest {
+    public static void main(String[] args) {
+        Subclass subclass = new Subclass();
+        // 调用默认方法
+        subclass.method2();
+        subclass.method3();
+
+        // 调用静态方法
+        CompareA.method1();
+    }
+}
+
+class Subclass implements CompareA {
+    // 重写接口的默认方法
+    public void method3() {
+        System.out.println("Subclass:method3");
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day22/USBTest.java b/javase/src/main/java/com/hongyi/day22/USBTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..bd8399c9dc989fa5ae96a4021facf82ea2ec2b8f
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day22/USBTest.java
@@ -0,0 +1,86 @@
+package com.hongyi.day22;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/15 15:50
+ * @Version 1.0
+ */
+public class USBTest {
+    public static void main(String[] args) {
+        Computer computer = new Computer();
+        // 1.创建了接口的非匿名实现类的非匿名对象
+        Flash flash = new Flash();
+        computer.transferData(flash); // 接口的多态性 USB usb = new Flash();
+
+        // 2.接口的非匿名实现类的匿名对象
+        computer.transferData(new Flash());
+
+        // 3.接口的匿名实现类的非匿名对象
+        USB phone = new USB() {
+            @Override
+            public void start() {
+                System.out.println("手机开始工作");
+            }
+
+            @Override
+            public void stop() {
+                System.out.println("手机结束工作");
+            }
+        };
+
+        computer.transferData(phone);
+
+        // 4.接口的匿名实现类的匿名对象
+        computer.transferData(new USB() {
+
+            @Override
+            public void start() {
+                System.out.println("mp3开始工作");
+            }
+
+            @Override
+            public void stop() {
+                System.out.println("mp3结束工作");
+            }
+        });
+    }
+}
+
+class Computer {
+    public void transferData(USB usb) {
+        usb.start();
+        System.out.println("具体的传输数据的细节");
+        usb.stop();
+    }
+}
+
+interface USB {
+    void start();
+
+    void stop();
+}
+
+class Flash implements USB {
+    @Override
+    public void start() {
+        System.out.println("U盘开始工作");
+    }
+
+    @Override
+    public void stop() {
+        System.out.println("U盘结束工作");
+    }
+}
+
+class Printer implements USB {
+
+    @Override
+    public void start() {
+        System.out.println("打印机开始工作");
+    }
+
+    @Override
+    public void stop() {
+        System.out.println("打印机结束工作");
+    }
+}
\ No newline at end of file
diff --git a/javase/src/main/java/com/hongyi/day23/InnerClassTest.java b/javase/src/main/java/com/hongyi/day23/InnerClassTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..ae0169a801c7acb32e159173017310a308efff6e
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day23/InnerClassTest.java
@@ -0,0 +1,63 @@
+package com.hongyi.day23;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/15 16:39
+ * @Version 1.0
+ */
+public class InnerClassTest {
+    public static void main(String[] args) {
+        // 创建Dog的实例
+        Person.Dog dog = new Person.Dog();
+        dog.run();
+
+        // 创建Bird的实例
+        Person person = new Person();
+        Person.Bird bird = person.new Bird();
+        bird.sing();
+        bird.display("Hongyi");
+    }
+}
+
+class Person {
+
+    String name = "Mark";
+    int age;
+
+    public void eat() {
+        System.out.println("Person eat");
+    }
+
+    // 静态成员内部类，只能调用外部静态的结构
+    static class Dog {
+        String name;
+        public Dog() {
+
+        }
+        public void run() {
+            System.out.println("Dog run");
+        }
+    }
+
+    // 非静态成员内部类
+    class Bird {
+        String name = "bird";
+        public Bird() {
+
+        }
+        public void sing() {
+            System.out.println("Bird sing");
+            Person.this.eat(); // 调用外部类的属性（完整格式）
+            // eat();
+        }
+
+        public void display(String name) {
+            // 方法的形参
+            System.out.println(name);
+            // 调用自己的属性
+            System.out.println(this.name);
+            // 外部类的属性
+            System.out.println(Person.this.name);
+        }
+    }
+}
diff --git a/javase/src/main/java/com/hongyi/day23/InnerClassTest1.java b/javase/src/main/java/com/hongyi/day23/InnerClassTest1.java
new file mode 100644
index 0000000000000000000000000000000000000000..65528ba548702fe78f8ba5df566e6831b7c59acf
--- /dev/null
+++ b/javase/src/main/java/com/hongyi/day23/InnerClassTest1.java
@@ -0,0 +1,12 @@
+package com.hongyi.day23;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/5/15 17:10
+ * @Version 1.0
+ */
+public class InnerClassTest1 {
+    public static void main(String[] args) {
+
+    }
+}
diff --git a/javase/src/test/java/com/hongyi/day6/FileTest.java b/javase/src/test/java/com/hongyi/day16/FileTest.java
similarity index 99%
rename from javase/src/test/java/com/hongyi/day6/FileTest.java
rename to javase/src/test/java/com/hongyi/day16/FileTest.java
index f855d902afd539154e639a98045e23dd6c8e76f6..3cae78e48190731a90dfd6a8c055a4078ed67cc0 100644
--- a/javase/src/test/java/com/hongyi/day6/FileTest.java
+++ b/javase/src/test/java/com/hongyi/day16/FileTest.java
@@ -1,4 +1,4 @@
-package com.hongyi.day6;
+package com.hongyi.day16;
 
 import org.junit.Test;
 
diff --git a/javase/src/test/java/com/hongyi/day17/WrapperTest.java b/javase/src/test/java/com/hongyi/day17/WrapperTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..e213ab857160bf1063755c4e092e5fd81f71bda5
--- /dev/null
+++ b/javase/src/test/java/com/hongyi/day17/WrapperTest.java
@@ -0,0 +1,15 @@
+package com.hongyi.day17;
+
+import org.junit.Test;
+
+/**
+ * @Author Kisugi Takumi
+ * @Date 2022/4/29 20:34
+ * @Version 1.0
+ */
+public class WrapperTest {
+    @Test
+    public void test0() {
+
+    }
+}