{"id":25047,"date":"2024-03-16T04:16:12","date_gmt":"2024-03-16T04:16:12","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-use-the-java-runtime-constant-pool\/"},"modified":"2024-03-22T05:13:42","modified_gmt":"2024-03-22T05:13:42","slug":"how-to-use-the-java-runtime-constant-pool","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-use-the-java-runtime-constant-pool\/","title":{"rendered":"How to use the Java runtime constant pool?"},"content":{"rendered":"<p>The Java runtime constant pool is a part of the class file that stores literals and symbol references generated by the compiler. At runtime, the Java Virtual Machine loads these constants into memory and references them when needed.<\/p>\n<p>The method of using the Java Runtime constant pool is as follows:<\/p>\n<ol>\n<li>Direct literal usage: you can directly use literals from the constant pool, for example, string constants can directly use string objects from the constant pool.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">str1<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">\"Hello\"<\/span>; <span class=\"hljs-comment\">\/\/ \u76f4\u63a5\u4f7f\u7528\u5e38\u91cf\u6c60\u4e2d\u7684\u5b57\u7b26\u4e32\u5bf9\u8c61<\/span>\r\n<span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">str2<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">String<\/span>(<span class=\"hljs-string\">\"Hello\"<\/span>); <span class=\"hljs-comment\">\/\/ \u521b\u5efa\u65b0\u7684\u5b57\u7b26\u4e32\u5bf9\u8c61<\/span>\r\n<\/code><\/pre>\n<ol>\n<li>Symbolic references are used: In Java virtual machine, classes, methods, fields, etc. are stored as symbolic references in the constant pool, which can be accessed to access corresponding class, method, field information.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code>Class&lt;?&gt; clazz = Class.forName(<span class=\"hljs-string\">\"java.lang.String\"<\/span>); <span class=\"hljs-comment\">\/\/ \u4f7f\u7528\u7b26\u53f7\u5f15\u7528\u83b7\u53d6\u7c7b\u5bf9\u8c61<\/span>\r\n<span class=\"hljs-type\">Method<\/span> <span class=\"hljs-variable\">method<\/span> <span class=\"hljs-operator\">=<\/span> clazz.getMethod(<span class=\"hljs-string\">\"length\"<\/span>); <span class=\"hljs-comment\">\/\/ \u4f7f\u7528\u7b26\u53f7\u5f15\u7528\u83b7\u53d6\u65b9\u6cd5\u5bf9\u8c61<\/span>\r\n<span class=\"hljs-type\">Field<\/span> <span class=\"hljs-variable\">field<\/span> <span class=\"hljs-operator\">=<\/span> clazz.getField(<span class=\"hljs-string\">\"CASE_INSENSITIVE_ORDER\"<\/span>); <span class=\"hljs-comment\">\/\/ \u4f7f\u7528\u7b26\u53f7\u5f15\u7528\u83b7\u53d6\u5b57\u6bb5\u5bf9\u8c61<\/span>\r\n<\/code><\/pre>\n<ol>\n<li>Optimization of constant pool: The Java runtime constant pool has the function of constant pool caching, which can prevent the creation of duplicate literal objects.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">str1<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">\"Hello\"<\/span>; <span class=\"hljs-comment\">\/\/ \u521b\u5efa\u65b0\u7684\u5b57\u7b26\u4e32\u5bf9\u8c61<\/span>\r\n<span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">str2<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">\"Hello\"<\/span>; <span class=\"hljs-comment\">\/\/ \u76f4\u63a5\u4f7f\u7528\u5e38\u91cf\u6c60\u4e2d\u7684\u5b57\u7b26\u4e32\u5bf9\u8c61<\/span>\r\nSystem.out.println(str1 == str2); <span class=\"hljs-comment\">\/\/ \u8f93\u51fatrue<\/span>\r\n<\/code><\/pre>\n<p>It should be noted that the specific implementation of the Java runtime constant pool may vary depending on the Java virtual machine. The above usage method is applicable to most Java virtual machines. In some special cases, it may be necessary to optimize and adjust according to the specific Java virtual machine.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Java runtime constant pool is a part of the class file that stores literals and symbol references generated by the compiler. At runtime, the Java Virtual Machine loads these constants into memory and references them when needed. The method of using the Java Runtime constant pool is as follows: Direct literal usage: you can [&hellip;]<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-25047","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How to use the Java runtime constant pool? - Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/blog\/how-to-use-the-java-runtime-constant-pool\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to use the Java runtime constant pool?\" \/>\n<meta property=\"og:description\" content=\"The Java runtime constant pool is a part of the class file that stores literals and symbol references generated by the compiler. 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