protected void finalize() throws Throwable {
    // 清理資源的代碼
}

public class ResourceHolder {
    private File file;
    
    public ResourceHolder(String fileName) {
        try {
            file = new File(fileName); // 打開文件進(jìn)行操作
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    @Override
    protected void finalize() throws Throwable {
        try {
            if (file != null) {
                file.close(); // 在對象被回收前關(guān)閉文件
            }
        } finally {
            super.finalize();
        }
    }
}

public class CacheObject {
    private int[] cache;
    
    public CacheObject(int size) {
        cache = new int[size]; // 初始化緩存數(shù)據(jù)
    }
    
    @Override
    protected void finalize() throws Throwable {
        // 清理緩存數(shù)據(jù)
        for (int i = 0; i < cache.length; i++) {
            cache[i] = 0;
        }
        cache = null;
        super.finalize();
    }
}

class SelfCleaningObject {
    private boolean isCleaned;
    
    public void clean() {
        isCleaned = true;
    }
    
    @Override
    protected void finalize() throws Throwable {
        if (!isCleaned) {
            // 進(jìn)行自我清理操作
            System.out.println("Performing self-cleaning.");
            isCleaned = true;
        }
        super.finalize();
    }
}

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class FinalizeExample {
    private FileWriter fileWriter;
    
    public FinalizeExample() {
        try {
            File file = new File("data.txt");
            fileWriter = new FileWriter(file);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    @Override
    protected void finalize() throws Throwable {
        try {
            if (fileWriter != null) {
                fileWriter.close();
                System.out.println("File resources cleaned up in finalize().");
            }
        } finally {
            super.finalize();
        }
    }
    
    public static void main(String[] args) {
        FinalizeExample obj = new FinalizeExample();
        System.out.println("Object created with hash code: " + obj.hashCode());
        
        obj = null; // 切斷引用，使對象成為垃圾
        
        // 建議JVM執(zhí)行垃圾回收
        System.gc();
        System.out.println("Requested garbage collection.");
        
        // 等待一段時間，讓垃圾回收有機會執(zhí)行
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        
        System.out.println("End of program.");
    }
}

public class FinalizeResurrection {
    public static FinalizeResurrection resurrectedObject = null;
    
    @Override
    protected void finalize() throws Throwable {
        super.finalize();
        resurrectedObject = this; // 使對象復(fù)活
    }
    
    public static void main(String[] args) throws InterruptedException {
        FinalizeResurrection obj = new FinalizeResurrection();
        obj = null; // 切斷引用
        System.gc(); // 建議垃圾回收
        
        // 等待finalize()方法執(zhí)行
        Thread.sleep(1000);
        
        if (resurrectedObject != null) {
            System.out.println("Object has been resurrected!");
        } else {
            System.out.println("Object has not been resurrected.");
        }
        
        resurrectedObject = null; // 再次切斷引用
        System.gc(); // 再次建議垃圾回收
        Thread.sleep(1000);
        
        if (resurrectedObject == null) {
            System.out.println("Object is finally garbage collected.");
        }
    }
}

public class MemoryLeakExample {
    private static final List<MemoryLeakExample> instances = new ArrayList<>();
    
    public MemoryLeakExample() {
        instances.add(this);
    }
    
    @Override
    protected void finalize() throws Throwable {
        instances.remove(this);
    }
}

public class TryWithResourcesExample {
    public static void main(String[] args) {
        try (FileWriter fileWriter = new FileWriter("data.txt")) {
            fileWriter.write("Hello, World!");
        } catch (IOException e) {
            e.printStackTrace();
        }
        // fileWriter會自動關(guān)閉，無需在finalize()中處理
    }
}

public class ExplicitResourceRelease {
    public static void main(String[] args) {
        FileWriter fileWriter = null;
        try {
            fileWriter = new FileWriter("data.txt");
            fileWriter.write("Hello, World!");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fileWriter != null) {
                try {
                    fileWriter.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

public class ObjectPoolExample {
    private static final List<PoolableObject> pool = new ArrayList<>();
    
    public static PoolableObject acquire() {
        if (!pool.isEmpty()) {
            return pool.remove(0);
        }
        return new PoolableObject();
    }
    
    public static void release(PoolableObject obj) {
        obj.reset();
        pool.add(obj);
    }
}
class PoolableObject {
    // 對象狀態(tài)
    private String state;
    
    public void use(String newState) {
        this.state = newState;
    }
    
    public void reset() {
        this.state = null;
    }
}