diff --git a/代码库2 b/代码库2
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+第1题：
+import java.util.Scanner;
+
+/**
+ * 任务：求N以内最大的10个素数之和。
+ */
+public class Educode {
+    public static void main(String[] args) {
+        // Input
+        Scanner input = new Scanner(System.in);
+        int n = input.nextInt();
+        // Caculate
+        int count = 0, sum = 0;
+        int i, j;
+        for (i = n; i >= 2; i--) {
+            for (j = 2; j < i; j++) {
+                if (i % j == 0)
+                    break;
+            }
+            if (i == j) {
+                sum += i;
+                count++;
+                if (count == 10)
+                    break;
+            }
+        }
+        // Output
+        System.out.println(sum);
+    }
+}
+
+第2题：
+import java.util.Scanner;
+
+/**
+ * 主程序类 Educode
+ */
+public class Educode {
+    public static void main(String[] args) {
+        // Input
+        Scanner in = new Scanner(System.in);
+        int id = in.nextInt();
+        String name = in.next();
+        double balance = in.nextDouble();
+        double annualInterestRate = in.nextDouble();
+        // Caculate
+        Account account = new Account(id, name, balance, annualInterestRate);
+        account.withdraw(2500);
+        account.deposit(3000);
+        // Output
+        account.print();
+    }
+}
+
+// 银行账户类 Account
+class Account {
+    /********** Begin **********/
+    // 4个私有属性 id name balance annualInterestRate
+    private int id;
+    private String name;
+    private double balance;
+    private double annualInterestRate;
+
+    // 有参构造方法
+    public Account(int id, String name, double balance, double annualInterestRate) {
+        this.id = id;
+        this.name = name;
+        this.balance = balance;
+        this.annualInterestRate = annualInterestRate;
+    }
+
+    // Setter & Getter 方法
+    public void setID(int id) {
+        this.id = id;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void setBalance(double balance) {
+        this.balance = balance;
+    }
+
+    public void setAnnualInterestRate(double annualInterestRate) {
+        this.annualInterestRate = annualInterestRate;
+    }
+
+    public int getID() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public double getBalance() {
+        return balance;
+    }
+
+    public double getAnnualInterestRate() {
+        return annualInterestRate;
+    }
+
+    // 业务方法 withdraw(double amount)，从账户中取特定数额的款。
+    public boolean withdraw(double amount) {
+        if (amount <= balance) {
+            balance -= amount;
+            return true;
+        } else
+            return false;
+    }
+
+    // 业务方法 deposit(double amount)，往账户中存特定数额的款。
+    public void deposit(double amount) {
+        balance += amount;
+    }
+
+    // 业务方法 getMonthlyInterestRate()，返回月利率
+    public double getMonthlyInterestRate() {
+        return annualInterestRate / 1200;
+    }
+
+    // 业务方法 print()，输出账户信息（账号、姓名、存款金额、月利率）
+    public void print() {
+        System.out.println(id);
+        System.out.println(name);
+        System.out.println(balance);
+        System.out.println(getMonthlyInterestRate() + "%");
+    }
+    /********** End **********/
+}
+
+第3题：
+import java.util.Scanner;
+
+/**
+ * 主程序类 TestAnimal
+ */
+public class TestAnimal {
+    public static void main(String[] args) {
+        // Input
+        Scanner input = new Scanner(System.in);
+        int n = input.nextInt(); //动物个数
+        Animal as[] = new Animal[n];
+        String name;  // 动物名称 ("Dog"、"Cat"、"Wolf")
+        /********** Begin **********/
+        // 输入 n 个具体动物 (Dog、Cat、Wolf)
+        for (int i = 0; i < n; i++) {
+            name = input.next();
+            if (name.equals("Dog"))
+                as[i] = new Dog();
+            else if (name.equals("Cat"))
+                as[i] = new Cat();
+            else if (name.equals("Wolf"))
+                as[i] = new Wolf();
+        }
+        //调用 as 数组中所有动物的 eat()方法
+        for (int i = 0; i < as.length; i++) {
+            as[i].eat();
+        }
+        //调用 as 数组中所有宠物的 play()方法
+        for (int i = 0; i < as.length; i++) {
+            if (as[i] instanceof Pet) {
+                Pet p = (Pet) as[i];
+                p.play();
+            }
+        }
+        /********** End **********/
+    }
+}
+
+abstract class Animal {
+    public abstract void eat();
+}
+
+interface Pet {
+    void play();
+}
+
+/*************** Begin ***************/
+// Dog 类，继承 Animal类，实现 Pet接口
+class Dog extends Animal implements Pet {
+    public void eat() {
+        System.out.println("Dog eat bones");
+    }
+
+    public void play() {
+        System.out.println("Play with Dog");
+    }
+}
+
+// Cat 类，继承 Animal类，实现 Pet接口
+class Cat extends Animal implements Pet {
+    public void eat() {
+        System.out.println("Cat eat fish");
+    }
+
+    public void play() {
+        System.out.println("Play with Cat");
+    }
+}
+
+// Wolf 类，继承 Animal类
+class Wolf extends Animal {
+    public void eat() {
+        System.out.println("Wolf eat meat");
+    }
+}
+/*************** End ***************/
+
+第4题：
+import java.util.Scanner;
+
+/******** Begin ********/
+// 任务1 - 使用继承 Thread 类的方式，定义线程类 MyThread1
+class MyThread1 extends Thread {
+    // 私有属性 n
+    private int n;
+
+    // 有参构造方法
+    public MyThread1(int n) {
+        this.n = n;
+    }
+
+    // 重写 run()方法 -- 每次输出一个整数值后 sleep(400) 注意：sleep要捕获 InterruptedException异常
+    public void run() {
+        for (int i = 1; i <= n; i++) {
+            System.out.println(Thread.currentThread().getName() + ": " + i);
+            try {
+                Thread.sleep(400);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+
+}
+
+// 任务2 - 使用实现 Runnable 接口的方式，定义线程类 MyThread2
+class MyThread2 implements Runnable {
+    // 私有属性 n
+    private int n;
+
+    // 有参构造方法
+    public MyThread2(int n) {
+        this.n = n;
+    }
+
+    // 重写 run()方法 -- 每次输出一个小写字母后 sleep(400) 注意：sleep要捕获 InterruptedException异常
+    public void run() {
+        for (int i = 0; i < n; i++) {
+            System.out.println(Thread.currentThread().getName() + ": " + (char) ('z' - i));
+            try {
+                Thread.sleep(400);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}
+
+/******** End ********/
+
+/**
+ * 主程序类 EduCode
+ */
+public class EduCode {
+    public static void main(String[] args) {
+        // 1-输入 n
+        Scanner input = new Scanner(System.in);
+        int n = input.nextInt();
+        // 2-创建线程1
+        MyThread1 t1 = new MyThread1(n);
+        t1.setName("线程1");
+        t1.setPriority(Thread.MIN_PRIORITY);
+        // 3-创建线程2
+        Thread t2 = new Thread(new MyThread2(n), "线程2");
+        t2.setPriority(Thread.MAX_PRIORITY);
+        // 4-启动线程
+        /******** Begin ********/
+        t1.start();
+        t2.start();
+        
+        /******** End ********/
+    }
+}
+