import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class CollectionsExample {
public static void main(String[] args) {
// List示例
List fruits = new ArrayList<>();
fruits.add(“Apple”);
fruits.add(“Banana”);
fruits.add(“Orange”);
System.out.println(“Fruits: ” + fruits);

// Set示例
Set uniqueFruits = new HashSet<>();
uniqueFruits.add(“Apple”);
uniqueFruits.add(“Banana”);
uniqueFruits.add(“Apple”); // 重复元素不会被添加
System.out.println(“Unique Fruits: ” + uniqueFruits);

// Map示例
Map fruitPrices = new HashMap<>();
fruitPrices.put(“Apple”, 10);
fruitPrices.put(“Banana”, 5);
fruitPrices.put(“Orange”, 8);
System.out.println(“Fruit Prices: ” + fruitPrices);
System.out.println(“Apple Price: ” + fruitPrices.get(“Apple”));
}
}

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileIOExample {
public static void main(String[] args) {
// 写入文件
try (BufferedWriter writer = new BufferedWriter(new FileWriter(“example.txt”))) {
writer.write(“Hello, Java I/O!”);
writer.newLine();
writer.write(“This is a test file.”);
} catch (IOException e) {
e.printStackTrace();
}

// 读取文件
try (BufferedReader reader = new BufferedReader(new FileReader(“example.txt”))) {
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}

// 运行结果
# java FileIOExample
Hello, Java I/O!
This is a test file.

public class ExceptionHandlingExample {
public static void main(String[] args) {
try {
// 可能抛出异常的代码
int result = divide(10, 0);
System.out.println(“Result: ” + result);
} catch (ArithmeticException e) {
// 捕获异常
System.out.println(“Error: ” + e.getMessage());
} finally {
// 无论是否发生异常都会执行的代码
System.out.println(“Execution completed.”);
}
}

public static int divide(int a, int b) {
if (b == 0) {
throw new ArithmeticException(“Division by zero”);
}
return a / b;
}
}

// 运行结果
# java ExceptionHandlingExample
Error: Division by zero
Execution completed.

public class ThreadExample extends Thread {
private String threadName;

public ThreadExample(String name) {
this.threadName = name;
}

@Override
public void run() {
System.out.println(“Thread ” + threadName + ” is running”);
try {
for (int i = 1; i <= 5; i++) { System.out.println("Thread " + threadName + ": " + i); Thread.sleep(1000); } } catch (InterruptedException e) { System.out.println("Thread " + threadName + " interrupted"); } System.out.println("Thread " + threadName + " finished"); } public static void main(String[] args) { ThreadExample thread1 = new ThreadExample("1"); ThreadExample thread2 = new ThreadExample("2"); thread1.start(); thread2.start(); } } // 运行结果 # java ThreadExample Thread 1 is running Thread 1: 1 Thread 2 is running Thread 2: 1 Thread 1: 2 Thread 2: 2 Thread 1: 3 Thread 2: 3 Thread 1: 4 Thread 2: 4 Thread 1: 5 Thread 2: 5 Thread 1 finished Thread 2 finished