{"id":156983,"date":"2020-09-12T06:31:47","date_gmt":"2020-09-11T22:31:47","guid":{"rendered":"http:\/\/4563.org\/?p=156983"},"modified":"2020-09-12T06:31:47","modified_gmt":"2020-09-11T22:31:47","slug":"%e6%88%91%e5%af%b9-jvm-%e7%9a%84-loading-constraints-%e7%90%86%e8%a7%a3%e6%ad%a3%e7%a1%ae%e5%90%97%ef%bc%9f","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=156983","title":{"rendered":"\u6211\u5bf9 JVM \u7684 Loading Constraints \u7406\u89e3\u6b63\u786e\u5417\uff1f"},"content":{"rendered":"<div>\n<div>\n<div>\n<h1>                  \u6211\u5bf9 JVM \u7684 Loading Constraints \u7406\u89e3\u6b63\u786e\u5417\uff1f               <\/h1>\n<p> <\/p>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : JasonLaw <\/span>  <span><i><\/i> 7<\/span> <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div isfirst=\"1\"> <\/p>\n<p>Java Virtual Machine Specification &#8211; Chapter 5. Loading, Linking, and Initializing &#8211; 5.3. Creation and Loading &#8211; 5.3.4. Loading Constraints\u4ecb\u7ecd\u4e86 Loading Constraints \u3002<\/p>\n<p>\u5047\u8bbe\u6709\u5982\u4e0b\u4ee3\u7801\uff1a<\/p>\n<pre><code>class Cat {     public static void main(String[] args) {         System.out.println(Mouse.ct);     } } <\/code><\/pre>\n<pre><code>class Mouse {     public static final CustomType ct = new CustomType(); } <\/code><\/pre>\n<pre><code>class CustomType {} <\/code><\/pre>\n<p><code>Cat<\/code>\u4f7f\u7528\u4e86<code>Mouse.ct<\/code>\uff0c\u6240\u4ee5\u5b83\u7684\u5e38\u91cf\u6c60\u4f1a\u5305\u542b\u6307\u5411<code>CustomType<\/code>\u7684\u4e00\u4e2a symbolic reference \u3002<code>Mouse<\/code>\u5b9a\u4e49\u4e86<code>public static final CustomType ct<\/code>\uff0c\u6240\u4ee5\u5b83\u7684\u5e38\u91cf\u6c60\u4e5f\u4f1a\u5305\u542b\u6307\u5411<code>CustomType<\/code>\u7684\u4e00\u4e2a symbolic reference \u3002<\/p>\n<p>\u6211\u7406\u89e3\u7684 Loading Constraints \u662f\uff1a\u5982\u679c class loader L1 \u53d1\u8d77\u5bf9<code>Cat<\/code>\u7684\u52a0\u8f7d\uff0c<code>class loader L2<\/code>\u53d1\u8d77\u5bf9<code>Mouse<\/code>\u7684\u52a0\u8f7d\u3002\u5173\u4e8e\u4e24\u8005\u5e38\u91cf\u6c60\u4e2d\u90fd\u5305\u542b\u7684\u6307\u5411<code>CustomType<\/code>\u7684 symbolic reference\uff0c\u6700\u540e\u8981\u4fdd\u8bc1 L1 \u548c L2 \u6240\u83b7\u5f97\u7684 java.lang.Class instance \u662f\u540c\u4e00\u4e2a\uff0c\u800c\u4e14 java.lang.Class instance \u6240\u5173\u8054\u7684 method area \u4e2d\u7684\u7c7b\u578b\u4fe1\u606f\u4e5f\u662f\u540c\u4e00\u4e2a\u3002<\/p>\n<p>\u8bf7\u95ee\u6211\u7684\u7406\u89e3\u6b63\u786e\u5417\uff1f<\/p>\n<\/p><\/div>\n<div> <b>\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (<span>0<\/span>)        <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<ul>\n<li>\n","protected":false},"excerpt":{"rendered":"<p>\u6211\u5bf9 JVM \u7684 Loading &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/156983"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=156983"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/156983\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=156983"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=156983"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=156983"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}