javajava Integer 缓存 一定是 -128~127 吗

Posted 2022-04-04 九师兄

1.概述

我们都知道 java Integer是有缓存的，缓存范围是 -128~127。但是这个值是一定的吗？

不一定。看源码。缓存大小居然可以改变

/**
     * Cache to support the object identity semantics of autoboxing for values between
     * -128 and 127 (inclusive) as required by JLS.
     *
     * The cache is initialized on first usage.  The size of the cache
     * may be controlled by the @code -XX:AutoBoxCacheMax=<size> option.
     * During VM initialization, java.lang.Integer.IntegerCache.high property
     * may be set and saved in the private system properties in the
     * sun.misc.VM class.
     */

    /*
     * Integer缓存，默认缓