Java 堆内存分区的实现示例

public class YoungGenerationExample {
    public static void main(String[] args) {
        for (int i = 0; i < 1000; i++) {
            // 创建短生命周期的对象，分配在 Eden 区
            byte[] array = new byte[1024 * 1024];
        }
    }
}

public class OldGenerationExample {
    public static void main(String[] args) {
        // 创建生命周期较长的对象
        byte[] array = new byte[10 * 1024 * 1024];
        // 让对象存活，防止被回收
        while (true) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

public class MetaspaceExample {
    public static void main(String[] args) {
        // 创建大量类加载操作，增加元空间的使用
        for (int i = 0; i < 10000; i++) {
            ClassLoader loader = new DynamicClassLoader();
            try {
                Class<?> clazz = loader.loadClass("example.MyClass" + i);
                Object instance = clazz.newInstance();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

class DynamicClassLoader extends ClassLoader {
    @Override
    public Class<?> findClass(String name) throws ClassNotFoundException {
        byte[] b = loadClassData(name);
        return defineClass(name, b, 0, b.length);
    }

    private byte[] loadClassData(String name) {
        // 动态生成字节码
        return new byte[0];
    }
}