在 Java 9 里对 IntegerCache 进行修改？

import java.lang.reflect.Field;

import java.util.Random;

public class Entropy {

public static void main(String[] args)

throws Exception {

// Extract the IntegerCache through reflection

//获取类

Class < ? > clazz = Class.forName(

"java.lang.Integer$IntegerCache");

//获取cache成员变量

Field field = clazz.getDeclaredField("cache");

field.setAccessible(true);

Integer[] cache = (Integer[]) field.get(clazz);

// Rewrite the Integer cache

for (int i = 0; i < cache.length; i++) {

cache[i] = new Integer(

new Random().nextInt(cache.length));

}

// Prove randomness

for (int i = 0; i < 10; i++) {

System.out.println((Integer) i);

}

}

}

Exception in thread "main" java.lang.reflect.InaccessibleObjectException:

Unable to make field static final java.lang.Integer[]

java.lang.Integer$IntegerCache.cache

accessible: module java.base does not "opens java.lang" to unnamed module @1bc6a36e