jvm_内存溢出_本机直接内存溢出

来源：互联网发布：黑莓passport转制软件编辑：程序博客网时间：2024/06/01 10:42

DirectMemory容量可通过-XX:MaxDirectMemorySize指定，如果不指定，则默认与Java堆的最大值（-Xxm指定）一样。下面的例子直接通过反射获取Unsafe实例并进行内存分配。
例：

package jvm;import java.lang.reflect.Field;/** * -XX:MaxDirectMemorySize=10M *  * @author Poison * */class DirectMemoryOOM {    private static final int _1MB = 1024 * 1024;    public static void main(String[] args) throws IllegalArgumentException,            IllegalAccessException {        Field unsafeField = sun.misc.Unsafe.class.getDeclaredFields()[0];        unsafeField.setAccessible(true);        sun.misc.Unsafe unsafe = (sun.misc.Unsafe) unsafeField.get(null);        while (true) {            unsafe.allocateMemory(_1MB);        }    }}

运行结果：
Exception in thread “main” java.lang.OutOfMemoryError
at sun.misc.Unsafe.allocateMemory(Native Method)
at jvm.DirectMemoryOOM.main(DirectMemoryOOM.java:19)

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