{"id":742,"date":"2023-01-02T22:27:10","date_gmt":"2023-05-11T17:05:55","guid":{"rendered":"https:\/\/www.silicloud.com\/ja\/blog\/index.php\/2023\/11\/30\/%e3%80%8cjava-14%e3%81%ae%e7%89%b9%e5%be%b4%e3%80%8d\/"},"modified":"2025-08-01T02:05:42","modified_gmt":"2025-07-31T17:05:42","slug":"%e3%80%8cjava-14%e3%81%ae%e7%89%b9%e5%be%b4%e3%80%8d","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/ja\/blog\/%e3%80%8cjava-14%e3%81%ae%e7%89%b9%e5%be%b4%e3%80%8d\/","title":{"rendered":"\u300cJava 14\u306e\u7279\u5fb4\u300d"},"content":{"rendered":"<p>6\u30f6\u6708\u30b5\u30a4\u30af\u30eb\u306e\u4f1d\u7d71\u3092\u5b88\u308b\u305f\u3081\u3001Java 13\u304c2019\u5e749\u670817\u65e5\u306b\u30ea\u30ea\u30fc\u30b9\u3055\u308c\u305f\u5f8c\u3001Java 14\u3001\u3082\u30461\u3064\u306e\u975eLTS\u30d0\u30fc\u30b8\u30e7\u30f3\u306f2020\u5e743\u670817\u65e5\u306b\u30ea\u30ea\u30fc\u30b9\u4e88\u5b9a\u3067\u3059\u3002<\/p>\n<h2>Java 14\u306e\u6a5f\u80fd<\/h2>\n<p>\u4ee5\u4e0b\u306bJava 14\u306e\u6a5f\u80fd\u306e\u30ea\u30b9\u30c8\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<ul class=\"post-ul\">\n<li>Switch Expressions (Standard) &#8211; JEP 361<\/li>\n<li>Pattern Matching for instanceof (Preview) &#8211; JEP 305<\/li>\n<li>Helpful NullPointerExceptions &#8211; JEP 358<\/li>\n<li>Records (Preview) &#8211; JEP 359<\/li>\n<li>Text Blocks (Second Preview) &#8211; JEP 368<\/li>\n<li>Packaging Tool (Incubator) &#8211; JEP 343<\/li>\n<li>NUMA-Aware Memory Allocation for G1 &#8211; JEP 345<\/li>\n<li>JFR Event Streaming &#8211; JEP 349<\/li>\n<li>Non-Volatile Mapped Byte Buffers &#8211; JEP 352<\/li>\n<li>ZGC on macOS &#8211; JEP 364<\/li>\n<li>ZGC on Windows &#8211; JEP 365<\/li>\n<li>Foreign-Memory Access API (Incubator) &#8211; JEP 370<\/li>\n<\/ul>\n<h2>\u30de\u30c3\u30afOS\u4e0a\u3067\u306eJava 14\u306e\u30a4\u30f3\u30b9\u30c8\u30fc\u30eb\u8a2d\u5b9a<\/h2>\n<ul class=\"post-ul\">\n<li>To get started with Java 14, download the JDK from here.<\/li>\n<li>Copy and extract the tar file in the \/Library\/Java\/JavaVirtualMachines as shown below:<\/li>\n<\/ul>\n<pre class=\"post-pre\"><code>$ <span class=\"token builtin class-name\">cd<\/span> \/Library\/Java\/JavaVirtualMachines\r\n\r\n$ <span class=\"token function\">sudo<\/span> <span class=\"token function\">cp<\/span> ~\/Downloads\/openjdk-14_osx-x64_bin.tar.gz \/Library\/Java\/JavaVirtualMachines\r\n\r\n$ <span class=\"token function\">sudo<\/span> <span class=\"token function\">tar<\/span> xzf openjdk-14_osx-x64_bin.tar.gz\r\n\r\n$ <span class=\"token function\">sudo<\/span> <span class=\"token function\">rm<\/span> openjdk-14_osx-x64_bin.tar.gz\r\n<\/code><\/pre>\n<p>\u305d\u308c\u304c\u7d42\u4e86\u3057\u305f\u3089\u3001\u4efb\u610f\u306e\u30c6\u30ad\u30b9\u30c8\u30a8\u30c7\u30a3\u30bf\u3092\u4f7f\u7528\u3057\u3066 bash_profile \u3092\u958b\u304d\u307e\u3059\u3002\u79c1\u306f vim ~\/.bash_profile \u3092\u4f7f\u7528\u3057\u3066\u3044\u307e\u3059\u3002Java14\u306e\u30d1\u30b9\u3092JAVA_HOME\u306b\u8a2d\u5b9a\u3057\u3001\u5909\u66f4\u3092\u4fdd\u5b58\u3057\u3001\u5909\u66f4\u3092\u53cd\u6620\u3059\u308b\u305f\u3081\u306bsource ~\/.bash_profile \u3092\u5b9f\u884c\u3057\u307e\u3059\u3002<\/p>\n<pre class=\"post-pre\"><code>export JAVA_HOME=\/Library\/Java\/JavaVirtualMachines\/jdk-14.jdk\/Contents\/Home\r\n<\/code><\/pre>\n<p>\u3064\u3044\u306b\u3001Java 14\u3092\u4f7f\u3063\u305f\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u30b3\u30f3\u30d1\u30a4\u30eb\u3068\u5b9f\u884c\u6e96\u5099\u304c\u6574\u3044\u307e\u3057\u305f\u3002\u65b0\u3057\u3044Java 14\u306e\u6a5f\u80fd\u3092\u8fc5\u901f\u306b\u30c6\u30b9\u30c8\u3059\u308b\u305f\u3081\u306e\u5bfe\u8a71\u578bREPL\u30b3\u30de\u30f3\u30c9\u30e9\u30a4\u30f3\u30c4\u30fc\u30eb\u3067\u3042\u308bJShell\u3092\u4f7f\u7528\u3057\u307e\u3059\u3002<\/p>\n<p>Java 14\u3067\u30ea\u30ea\u30fc\u30b9\u3055\u308c\u305f\u591a\u304f\u306e\u6a5f\u80fd\u306f\u30d7\u30ec\u30d3\u30e5\u30fc\u7248\u3067\u3042\u308b\u3053\u3068\u306b\u6ce8\u610f\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002\u3064\u307e\u308a\u3001\u73fe\u6642\u70b9\u3067\u306f\u5b8c\u5168\u306b\u6a5f\u80fd\u3057\u3066\u3044\u308b\u3082\u306e\u306e\u3001\u5c06\u6765\u7684\u306b\u5909\u66f4\u3055\u308c\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002\u6b21\u306e\u30ea\u30ea\u30fc\u30b9\u30b5\u30a4\u30af\u30eb\u3067\u306f\u3001\u4e00\u90e8\u306e\u6a5f\u80fd\u304c\u6a19\u6e96\u5316\u3055\u308c\u308b\u304b\u3001\u5358\u7d14\u306b\u524a\u9664\u3055\u308c\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002\u30d7\u30ec\u30d3\u30e5\u30fc\u7248\u306e\u6a5f\u80fd\u3092\u30c6\u30b9\u30c8\u3059\u308b\u305f\u3081\u306b\u306f\u3001\u4ee5\u4e0b\u306b\u793a\u3059\u3088\u3046\u306b\u3001JShell\u3084Java\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u5b9f\u884c\u3059\u308b\u969b\u306b\u660e\u793a\u7684\u306b `&#8211;enable-preview` \u3092\u8a2d\u5b9a\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<pre class=\"post-pre\"><code>jshell --enable-preview\r\n\r\njavac <span class=\"token parameter variable\">--release<\/span> <span class=\"token number\">14<\/span> --enable-preview Author.java\r\n<\/code><\/pre>\n<p>\u6b21\u306e\u6570\u7bc0\u3067\u306f\u3001\u8a00\u8a9e\u3068JVM\u306e\u3044\u304f\u3064\u304b\u306e\u6a5f\u80fd\u306b\u3064\u3044\u3066\u8a71\u3057\u5408\u3044\u307e\u3057\u3087\u3046\u3002<\/p>\n<p>\u304a\u3059\u3059\u3081\u306e\u8aad\u307f\u7269: Linux\u306bJava 14\u3092\u30a4\u30f3\u30b9\u30c8\u30fc\u30eb\u3059\u308b\u65b9\u6cd5<\/p>\n<h2>1. \u30b9\u30a4\u30c3\u30c1\u5f0f\u306e\u8868\u73fe\u65b9\u6cd5<\/h2>\n<p>\u76f4\u8fd1\u306e2\u3064\u306e\u30ea\u30ea\u30fc\u30b9\u3067\u30d7\u30ec\u30d3\u30e5\u30fc\u6a5f\u80fd\u3068\u3057\u3066\u63d0\u4f9b\u3055\u308c\u305f\u30b9\u30a4\u30c3\u30c1\u5f0f\u306f\u3001\u3064\u3044\u306bJava 14\u3067\u6b63\u5f0f\u306a\u6a5f\u80fd\u3068\u3057\u3066\u8ffd\u52a0\u3055\u308c\u307e\u3057\u305f\u3002<\/p>\n<ul class=\"post-ul\">\n<li>Java 12 introduced the lambda syntax for switch expressions thereby allowing multiple case labels for pattern matching as well as preventing fall-throughs which lead to verbose code. It also enforced exhaustive cases wherein a compilation error would be thrown if all the input cases aren\u2019t covered.<\/li>\n<li>Java 13, the second preview introduced yield statements instead of break for returning values from an expression.<\/li>\n<\/ul>\n<p>\u3064\u3044\u306bJava 14\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u6a5f\u80fd\u304c\u6a19\u6e96\u3068\u306a\u308a\u307e\u3057\u305f\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"token class-name\">String<\/span> result <span class=\"token operator\">=<\/span> <span class=\"token keyword\">switch<\/span> <span class=\"token punctuation\">(<\/span>day<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n            <span class=\"token keyword\">case<\/span> <span class=\"token string\">\"M\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"W\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"F\"<\/span> <span class=\"token operator\">-&gt;<\/span> <span class=\"token string\">\"MWF\"<\/span><span class=\"token punctuation\">;<\/span>\r\n            <span class=\"token keyword\">case<\/span> <span class=\"token string\">\"T\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"TH\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"S\"<\/span> <span class=\"token operator\">-&gt;<\/span> <span class=\"token string\">\"TTS\"<\/span><span class=\"token punctuation\">;<\/span>\r\n            <span class=\"token keyword\">default<\/span> <span class=\"token operator\">-&gt;<\/span> <span class=\"token punctuation\">{<\/span>\r\n                <span class=\"token keyword\">if<\/span><span class=\"token punctuation\">(<\/span>day<span class=\"token punctuation\">.<\/span><span class=\"token function\">isEmpty<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span>\r\n                    <span class=\"token keyword\">yield<\/span> <span class=\"token string\">\"Please insert a valid day.\"<\/span><span class=\"token punctuation\">;<\/span>\r\n                <span class=\"token keyword\">else<\/span>\r\n                    <span class=\"token keyword\">yield<\/span> <span class=\"token string\">\"Looks like a Sunday.\"<\/span><span class=\"token punctuation\">;<\/span>\r\n            <span class=\"token punctuation\">}<\/span>\r\n\r\n        <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span>\r\n<span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span>result<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n<\/code><\/pre>\n<div><img decoding=\"async\" class=\"post-images\" title=\"\" src=\"https:\/\/cdn.silicloud.com\/blog-img\/blog\/img\/656497e4daa94e2bdf7c056b\/19-0.png\" alt=\"Java 14 Switch Expressions\" \/><\/div>\n<p>\u6ce8\u610f\uff1ayield\u306fJava\u3067\u65b0\u3057\u3044\u30ad\u30fc\u30ef\u30fc\u30c9\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u305d\u308c\u306f\u5358\u306bswitch\u5f0f\u3067\u4f7f\u7528\u3055\u308c\u307e\u3059\u3002<\/p>\n<h2>2. instanceof\u306b\u3088\u308b\u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u30f3\u30b0\uff08\u30d7\u30ec\u30d3\u30e5\u30fc\uff09<\/h2>\n<p>Java\u306e\u958b\u767a\u8005\u306b\u30b3\u30fc\u30c9\u30d9\u30fc\u30b9\u3092\u898b\u305b\u3066\u3082\u3089\u3048\u3070\u3001\u30b3\u30fc\u30c9\u5168\u4f53\u306b\u306finstanceof\u6761\u4ef6\u3092\u3046\u307e\u304f\u6d3b\u7528\u3057\u305f\u7b87\u6240\u304c\u898b\u3089\u308c\u307e\u3059\u3002\u5177\u4f53\u7684\u306b\u306f\u3001instanceof\u6761\u4ef6\u306e\u30c1\u30a7\u30c3\u30af\u306e\u5f8c\u306b\u306f\u4e00\u822c\u7684\u306b\u578b\u30ad\u30e3\u30b9\u30c8\u304c\u7d9a\u304d\u307e\u3059\u3002<\/p>\n<p>Java 14\u3067\u306f\u3001\u3053\u306e\u5197\u9577\u6027\u3092\u7121\u304f\u3057\u3066\u3001\u6761\u4ef6\u62bd\u51fa\u3092\u305a\u3063\u3068\u7c21\u6f54\u306b\u3057\u307e\u3059\u3002<\/p>\n<p>Java 14\u4ee5\u524d\uff1a<\/p>\n<pre class=\"post-pre\"><code><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>obj <span class=\"token keyword\">instanceof<\/span> <span class=\"token class-name\">Journaldev<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n  <span class=\"token class-name\">Journaldev<\/span> jd <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Journaldev<\/span><span class=\"token punctuation\">)<\/span> obj<span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span>jd<span class=\"token punctuation\">.<\/span><span class=\"token function\">getAuthor<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n<\/code><\/pre>\n<p>Java 14\u4ee5\u964d:<\/p>\n<pre class=\"post-pre\"><code><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>obj <span class=\"token keyword\">instanceof<\/span> <span class=\"token class-name\">Journaldev<\/span> jd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n  <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span>jd<span class=\"token punctuation\">.<\/span><span class=\"token function\">getAuthor<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n<\/code><\/pre>\n<p>\u4e0a\u8a18\u306e\u30b3\u30fc\u30c9\u3067\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304cJournaldev\u306e\u578b\u3067\u3042\u308b\u5834\u5408\u306b\u306e\u307f\u3001\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9jd\u304c\u5272\u308a\u5f53\u3066\u3089\u308c\u307e\u3059\u3002\u5909\u6570\u306e\u30b9\u30b3\u30fc\u30d7\u306f\u6761\u4ef6\u30d6\u30ed\u30c3\u30af\u306b\u9650\u5b9a\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<h2>3. \u4fbf\u5229\u306aNullPointerException<\/h2>\n<p>\u30cc\u30eb\u30dd\u30a4\u30f3\u30bf\u30fc\u30a8\u30af\u30bb\u30d7\u30b7\u30e7\u30f3\u306f\u3001\u3069\u3093\u306a\u958b\u767a\u8005\u306b\u3068\u3063\u3066\u3082\u60aa\u5922\u3067\u3059\u3002\u4ee5\u524d\u306eJava 13\u307e\u3067\u306f\u3001\u6709\u540d\u306aNPE\u306e\u30c7\u30d0\u30c3\u30b0\u304c\u96e3\u3057\u304b\u3063\u305f\u3067\u3059\u3002\u958b\u767a\u8005\u306f\u3001\u30b9\u30bf\u30c3\u30af\u30c8\u30ec\u30fc\u30b9\u306b\u884c\u756a\u53f7\u3057\u304b\u8868\u793a\u3055\u308c\u306a\u3044\u305f\u3081\u3001\u4ed6\u306e\u30c7\u30d0\u30c3\u30b0\u30c4\u30fc\u30eb\u3092\u4f7f\u3046\u304b\u3001\u624b\u52d5\u3067\u30cc\u30eb\u3068\u306a\u3063\u3066\u3044\u308b\u5909\u6570\/\u30e1\u30bd\u30c3\u30c9\u3092\u7279\u5b9a\u3057\u306a\u3051\u308c\u3070\u306a\u308a\u307e\u305b\u3093\u3067\u3057\u305f\u3002<\/p>\n<p>Java 14\u4ee5\u524d\u3067\u306f\uff1a<\/p>\n<pre class=\"post-pre\"><code><span class=\"token class-name\">String<\/span> name <span class=\"token operator\">=<\/span> jd<span class=\"token punctuation\">.<\/span><span class=\"token function\">getBlog<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">getAuthor<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span>\r\n\r\n<span class=\"token comment\">\/\/Stacktrace<\/span>\r\n<span class=\"token class-name\">Exception<\/span> in thread <span class=\"token string\">\"main\"<\/span> <span class=\"token class-name\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>lang<span class=\"token punctuation\">.<\/span><\/span>NullPointerException<\/span>\r\n    at <span class=\"token class-name\">NullPointerExample<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">NullPointerExample<\/span><span class=\"token punctuation\">.<\/span>java<span class=\"token operator\">:<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">)<\/span>\r\n<\/code><\/pre>\n<p>\u4ee5\u4e0b\u306b\u793a\u3059\u3088\u3046\u306a\u3088\u308a\u8a73\u7d30\u306a\u30b9\u30bf\u30c3\u30af\u60c5\u5831\u3092\u63d0\u4f9b\u3059\u308b\u3001Java 14\u3067\u65b0\u305f\u306b\u5c0e\u5165\u3055\u308c\u305fJVM\u306e\u65b0\u6a5f\u80fd\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"token class-name\">Exception<\/span> in thread <span class=\"token string\">\"main\"<\/span> <span class=\"token class-name\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>lang<span class=\"token punctuation\">.<\/span><\/span>NullPointerException<\/span><span class=\"token operator\">:<\/span> <span class=\"token class-name\">Cannot<\/span> invoke <span class=\"token string\">\"Blog.getAuthor()\"<\/span> because the <span class=\"token keyword\">return<\/span> value of <span class=\"token string\">\"Journaldev.getBlog()\"<\/span> is <span class=\"token keyword\">null<\/span>\r\n    at <span class=\"token class-name\">NullPointerExample<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">NullPointerExample<\/span><span class=\"token punctuation\">.<\/span>java<span class=\"token operator\">:<\/span><span class=\"token number\">4<\/span><span class=\"token punctuation\">)<\/span>\r\n<\/code><\/pre>\n<p>\u4e0a\u8a18\u306e\u6a5f\u80fd\u306f\u8a00\u8a9e\u306e\u6a5f\u80fd\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u305d\u308c\u306f\u30e9\u30f3\u30bf\u30a4\u30e0\u74b0\u5883\u306e\u6539\u826f\u3067\u3059\u3002<\/p>\n<h2>4. \u30ec\u30b3\u30fc\u30c9\uff08\u30d7\u30ec\u30d3\u30e5\u30fc\uff09<\/h2>\n<p>\u30ec\u30b3\u30fc\u30c9\u306f\u3001\u7d14\u7c8b\u306a\u30c7\u30fc\u30bf\u3092\u683c\u7d0d\u3059\u308b\u30c7\u30fc\u30bf\u30af\u30e9\u30b9\u3067\u3059\u3002\u30ec\u30b3\u30fc\u30c9\u3092\u5c0e\u5165\u3059\u308b\u76ee\u7684\u306f\u3001\u5197\u9577\u306a\u30b3\u30fc\u30c9\u306e\u306a\u3044\u3001\u7c21\u5358\u3067\u7c21\u6f54\u306a\u30af\u30e9\u30b9\u3092\u8fc5\u901f\u306b\u4f5c\u6210\u3059\u308b\u3053\u3068\u3067\u3059\u3002<\/p>\n<p>\u901a\u5e38\u3001Java\u306e\u30af\u30e9\u30b9\u3067\u306fequals()\u3001hashCode()\u3001\u30b2\u30c3\u30bf\u30fc\u3068\u30bb\u30c3\u30bf\u30fc\u306e\u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002\u4e00\u90e8\u306eIDE\u306f\u3001\u305d\u306e\u3088\u3046\u306a\u30af\u30e9\u30b9\u306e\u81ea\u52d5\u751f\u6210\u3092\u30b5\u30dd\u30fc\u30c8\u3057\u3066\u3044\u307e\u3059\u304c\u3001\u30b3\u30fc\u30c9\u306f\u307e\u3060\u5197\u9577\u3067\u3059\u3002record\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u6b21\u306e\u3088\u3046\u306b\u30af\u30e9\u30b9\u3092\u7c21\u5358\u306b\u5b9a\u7fa9\u3059\u308b\u3060\u3051\u3067\u6e08\u307f\u307e\u3059\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"token keyword\">record<\/span> <span class=\"token class-name\">Author<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span>\r\n<span class=\"token comment\">\/\/or<\/span>\r\n<span class=\"token keyword\">record<\/span> <span class=\"token class-name\">Author<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">String<\/span> topic<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span>\r\n<\/code><\/pre>\n<p>Java\u30b3\u30f3\u30d1\u30a4\u30e9\u306f\u3001\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3001\u30d7\u30e9\u30a4\u30d9\u30fc\u30c8\u306a\u6700\u7d42\u30d5\u30a3\u30fc\u30eb\u30c9\u3001\u30a2\u30af\u30bb\u30c3\u30b5\u3001equals\/hashCode\u3001\u304a\u3088\u3073toString\u30e1\u30bd\u30c3\u30c9\u3092\u81ea\u52d5\u7684\u306b\u751f\u6210\u3057\u307e\u3059\u3002\u4e0a\u8a18\u306e\u30af\u30e9\u30b9\u306e\u81ea\u52d5\u751f\u6210\u3055\u308c\u305f\u30b2\u30c3\u30bf\u30fc\u30e1\u30bd\u30c3\u30c9\u306f\u3001name()\u3068topic()\u3067\u3059\u3002<\/p>\n<p>javac\u3092\u4f7f\u7528\u3057\u3066\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u30b3\u30f3\u30d1\u30a4\u30eb\u3057\u305f\u5f8c\u3001\u751f\u6210\u3055\u308c\u305f\u30b3\u30fc\u30c9\u3092\u8abf\u3079\u308b\u306b\u306f\u3001javap Author\u3092\u4f7f\u7528\u3057\u307e\u3059\u3002\u6b21\u306e\u30a4\u30e9\u30b9\u30c8\u306f\u3001\u30ec\u30b3\u30fc\u30c9Author\uff08String name\u3001String topic\uff09{}\u306e\u751f\u6210\u3055\u308c\u305f\u30af\u30e9\u30b9\u3092\u793a\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<div><img decoding=\"async\" class=\"post-images\" title=\"\" src=\"https:\/\/cdn.silicloud.com\/blog-img\/blog\/img\/656497e4daa94e2bdf7c056b\/42-0.png\" alt=\"Javap Records Java 14\" \/><\/div>\n<p>\u30ec\u30b3\u30fc\u30c9\u306e\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u306f\u3001Kotlin\u306e\u30c7\u30fc\u30bf\u30af\u30e9\u30b9\u3068\u4f3c\u3066\u3044\u307e\u3059\u3002<\/p>\n<p>\u3055\u3089\u306b\u3001\u6b21\u306e\u3088\u3046\u306b\u3057\u3066\u30ec\u30b3\u30fc\u30c9\u306b\u8ffd\u52a0\u306e\u30d5\u30a3\u30fc\u30eb\u30c9\u3001\u30e1\u30bd\u30c3\u30c9\u3001\u304a\u3088\u3073\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3092\u8ffd\u52a0\u3059\u308b\u3053\u3068\u3082\u3067\u304d\u307e\u3059\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"token keyword\">record<\/span> <span class=\"token class-name\">Author<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> id<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">String<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">String<\/span> topic<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> followers<span class=\"token punctuation\">;<\/span>\r\n\r\n    <span class=\"token keyword\">public<\/span> <span class=\"token keyword\">static<\/span> <span class=\"token class-name\">String<\/span> <span class=\"token function\">followerCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token keyword\">return<\/span> <span class=\"token string\">\"Followers are \"<\/span><span class=\"token operator\">+<\/span> followers<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">String<\/span> <span class=\"token function\">description<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token keyword\">return<\/span> <span class=\"token string\">\"Author \"<\/span><span class=\"token operator\">+<\/span> name <span class=\"token operator\">+<\/span> <span class=\"token string\">\" writes on \"<\/span><span class=\"token operator\">+<\/span> topic<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">Author<\/span><span class=\"token punctuation\">{<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>id <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token keyword\">throw<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">IllegalArgumentException<\/span><span class=\"token punctuation\">(<\/span> <span class=\"token string\">\"id must be greater than 0.\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n     <span class=\"token punctuation\">}<\/span>\r\n   <span class=\"token punctuation\">}<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n<\/code><\/pre>\n<p>\u30ec\u30b3\u30fc\u30c9\u5185\u3067\u5b9a\u7fa9\u3055\u308c\u305f\u8ffd\u52a0\u306e\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u306f\u3001\u30b3\u30f3\u30d1\u30af\u30c8\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3068\u547c\u3070\u308c\u307e\u3059\u3002\u30d1\u30e9\u30e1\u30fc\u30bf\u3092\u6301\u305f\u305a\u3001\u30ab\u30ce\u30cb\u30ab\u30eb\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u306e\u62e1\u5f35\u3067\u3059\u3002<\/p>\n<p>\u30b3\u30f3\u30d1\u30af\u30c8\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u306f\u3001\u30b3\u30f3\u30d1\u30a4\u30e9\u306b\u3088\u3063\u3066\u5225\u3005\u306e\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3068\u3057\u3066\u751f\u6210\u3055\u308c\u307e\u305b\u3093\u3002\u4ee3\u308f\u308a\u306b\u3001\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u30b1\u30fc\u30b9\u3067\u4f7f\u7528\u3055\u308c\u3001\u30e1\u30a4\u30f3\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u306e\u958b\u59cb\u6642\u306b\u547c\u3073\u51fa\u3055\u308c\u307e\u3059\u3002<\/p>\n<p>\u30ec\u30b3\u30fc\u30c9\u306b\u3064\u3044\u3066\u6ce8\u610f\u3059\u3079\u304d\u91cd\u8981\u306a\u70b9\u306f\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002<\/p>\n<ul class=\"post-ul\">\n<li>A\u00a0record\u00a0can neither extend a class nor it can be extended by another class. It\u2019s a final class.<\/li>\n<li>Records cannot be abstract<\/li>\n<li>Records cannot extend any other class and cannot define instance fields inside the body. Instance fields must be defined in the state description only<\/li>\n<li>Declared fields are private and\u00a0final<\/li>\n<li>The body of a record allows static fields and methods<\/li>\n<\/ul>\n<p>\u304a\u3059\u3059\u3081\u306e\u8aad\u307f\u7269: Java Records<\/p>\n<h3>4.1) \u30ec\u30b3\u30fc\u30c9\u306e\u53c2\u7167\u30d5\u30a3\u30fc\u30eb\u30c9\u5185\u306e\u5024\u306f\u5909\u66f4\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/h3>\n<p>\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3068\u3057\u3066\u5b9a\u7fa9\u3055\u308c\u305f\u30d5\u30a3\u30fc\u30eb\u30c9\u306b\u95a2\u3057\u3066\u306f\u3001\u91cd\u8981\u306a\u3053\u3068\u306f\u3001\u53c2\u7167\u306e\u307f\u304c\u5909\u66f4\u4e0d\u53ef\u80fd\u3067\u3042\u308b\u3068\u3044\u3046\u3053\u3068\u3067\u3059\u3002\u5185\u90e8\u306e\u5024\u306f\u5909\u66f4\u53ef\u80fd\u3067\u3059\u3002\u6b21\u306e\u4f8b\u3067\u306f\u3001ArrayList\u304c\u5909\u66f4\u3055\u308c\u305f\u3068\u304d\u306b\u5024\u304c\u5909\u66f4\u3055\u308c\u308b\u30ec\u30b3\u30fc\u30c9\u304c\u793a\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u3054\u89a7\u306e\u3088\u3046\u306b\u3001ArrayList\u304c\u5909\u66f4\u3055\u308c\u308b\u305f\u3073\u306b\u5024\u304c\u5909\u66f4\u3055\u308c\u307e\u3059\u3002<\/p>\n<div><img decoding=\"async\" class=\"post-images\" title=\"\" src=\"https:\/\/cdn.silicloud.com\/blog-img\/blog\/img\/656497e4daa94e2bdf7c056b\/53-0.png\" alt=\"Java 14 Records Mutable Values For References\" \/><\/div>\n<h3>4.2) \u30ec\u30b3\u30fc\u30c9\u306f\u30a4\u30f3\u30bf\u30d5\u30a7\u30fc\u30b9\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/h3>\n<p>\u4ee5\u4e0b\u306e\u30b3\u30fc\u30c9\u306f\u3001\u30ec\u30b3\u30fc\u30c9\u3092\u4f7f\u7528\u3057\u305f\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u306e\u5b9f\u88c5\u4f8b\u3092\u793a\u3057\u3066\u3044\u307e\u3059\u3002 (I will be providing a single option)<\/p>\n<pre class=\"post-pre\"><code><span class=\"token keyword\">record<\/span> <span class=\"token class-name\">Author<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">String<\/span> topic<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">implements<\/span> <span class=\"token class-name\">Information<\/span> <span class=\"token punctuation\">{<\/span>\r\n  <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">String<\/span> <span class=\"token function\">getFullName<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n    <span class=\"token keyword\">return<\/span> <span class=\"token string\">\"Author \"<\/span><span class=\"token operator\">+<\/span> name <span class=\"token operator\">+<\/span> <span class=\"token string\">\" writes on \"<\/span> <span class=\"token operator\">+<\/span> topic<span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token punctuation\">}<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n\r\n<span class=\"token keyword\">interface<\/span> <span class=\"token class-name\">Information<\/span> <span class=\"token punctuation\">{<\/span>\r\n  <span class=\"token class-name\">String<\/span> <span class=\"token function\">getFullName<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n<\/code><\/pre>\n<p>\u4e0a\u8a18\u306e\u30b3\u30fc\u30c9\u3092\u5b9f\u884c\u3057\u305f\u7d50\u679c\u306f\u3001JShell\u3067\u306e\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u51fa\u529b\u3067\u3059\u3002<\/p>\n<div><img decoding=\"async\" class=\"post-images\" title=\"\" src=\"https:\/\/cdn.silicloud.com\/blog-img\/blog\/img\/656497e4daa94e2bdf7c056b\/58-0.png\" alt=\"Java 14 Records With Interface\" \/><\/div>\n<h3>4.3) \u30ec\u30b3\u30fc\u30c9\u306f\u8907\u6570\u306e\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3092\u30b5\u30dd\u30fc\u30c8\u3057\u3066\u3044\u307e\u3059\u3002<\/h3>\n<p>\u30ec\u30b3\u30fc\u30c9\u306f\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u3001\u30d1\u30e9\u30e1\u30fc\u30bf\u3042\u308a\u307e\u305f\u306f\u306a\u3057\u3067\u8907\u6570\u306e\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3092\u5ba3\u8a00\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"token keyword\">record<\/span> <span class=\"token class-name\">Author<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">String<\/span> topic<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n  <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">Author<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n\r\n    <span class=\"token keyword\">this<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"NA\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"NA\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token punctuation\">}<\/span>\r\n\r\n  <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">Author<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> name<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n\r\n    <span class=\"token keyword\">this<\/span><span class=\"token punctuation\">(<\/span>name<span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"NA\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token punctuation\">}<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n<\/code><\/pre>\n<h3>4.4) \u30ec\u30b3\u30fc\u30c9\u306b\u3088\u3063\u3066\u30a2\u30af\u30bb\u30b5\u30e1\u30bd\u30c3\u30c9\u306e\u4fee\u6b63\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002 (Rek\u014ddo ni yotte akusesa mesoddo no sh\u016bsei ga kan\u014d ni narimasu.)<\/h3>\n<p>\u30c7\u30fc\u30bf\u5b9a\u7fa9\u306b\u57fa\u3065\u3044\u3066\u30ec\u30b3\u30fc\u30c9\u304c\u516c\u958b\u30a2\u30af\u30bb\u30b5\u30e1\u30bd\u30c3\u30c9\u3092\u751f\u6210\u3059\u308b\u304c\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u672c\u4f53\u3067\u30a2\u30af\u30bb\u30b5\u30e1\u30bd\u30c3\u30c9\u3092\u518d\u5b9a\u7fa9\u3059\u308b\u3053\u3068\u3082\u3067\u304d\u307e\u3059\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"token keyword\">record<\/span> <span class=\"token class-name\">Author<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">String<\/span> topic<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n  <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">String<\/span> <span class=\"token function\">name<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token keyword\">return<\/span> <span class=\"token string\">\"This article was written by \"<\/span> <span class=\"token operator\">+<\/span> <span class=\"token keyword\">this<\/span><span class=\"token punctuation\">.<\/span>name<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n<\/code><\/pre>\n<h3>4.5) \u30e9\u30f3\u30bf\u30a4\u30e0\u3067\u306e\u30ec\u30b3\u30fc\u30c9\u3068\u305d\u306e\u69cb\u6210\u8981\u7d20\u306e\u78ba\u8a8d<\/h3>\n<p>\u30ec\u30b3\u30fc\u30c9\u306f\u3001isRecord()\u30e1\u30bd\u30c3\u30c9\u3068getRecordComponents()\u30e1\u30bd\u30c3\u30c9\u3092\u63d0\u4f9b\u3057\u3066\u304a\u308a\u3001\u30af\u30e9\u30b9\u304c\u30ec\u30b3\u30fc\u30c9\u304b\u3069\u3046\u304b\u3092\u78ba\u8a8d\u3057\u3001\u30d5\u30a3\u30fc\u30eb\u30c9\u3068\u578b\u3092\u8abf\u3079\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u4ee5\u4e0b\u306e\u56f3\u306f\u3001\u305d\u306e\u65b9\u6cd5\u3092\u793a\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<div><img decoding=\"async\" class=\"post-images\" title=\"\" src=\"https:\/\/cdn.silicloud.com\/blog-img\/blog\/img\/656497e4daa94e2bdf7c056b\/67-0.png\" alt=\"Java 14 Records Runtime Check\" \/><\/div>\n<p>\u4e0a\u8a18\u306e\u30b3\u30fc\u30c9\u4f8b\u3067\u306f\u3001\u8ffd\u52a0\u306e\u30d5\u30a3\u30fc\u30eb\u30c9\u3068\u30e1\u30bd\u30c3\u30c9\u3092\u30ec\u30b3\u30fc\u30c9\u306b\u8ffd\u52a0\u3057\u307e\u3057\u305f\u304c\u3001\u305d\u308c\u3092\u904e\u5ea6\u306b\u884c\u308f\u306a\u3044\u3088\u3046\u306b\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u30ec\u30b3\u30fc\u30c9\u306f\u3001\u5358\u306a\u308b\u30c7\u30fc\u30bf\u306e\u904b\u642c\u624b\u6bb5\u3068\u3057\u3066\u8a2d\u8a08\u3055\u308c\u3066\u304a\u308a\u3001\u591a\u304f\u306e\u8ffd\u52a0\u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\u3057\u305f\u3044\u5834\u5408\u306f\u3001\u901a\u5e38\u306e\u30af\u30e9\u30b9\u306b\u623b\u308b\u65b9\u304c\u826f\u3044\u3067\u3059\u3002<\/p>\n<h2>5. \u30c6\u30ad\u30b9\u30c8\u30d6\u30ed\u30c3\u30af\uff08\u30d7\u30ec\u30d3\u30e5\u30fc\uff09<\/h2>\n<p>\u30c6\u30ad\u30b9\u30c8\u30d6\u30ed\u30c3\u30af\u306f\u3001Java 13\u306e\u30d7\u30ec\u30d3\u30e5\u30fc\u6a5f\u80fd\u3068\u3057\u3066\u5c0e\u5165\u3055\u308c\u3001\u8907\u6570\u884c\u306e\u6587\u5b57\u5217\u30ea\u30c6\u30e9\u30eb\u306e\u7c21\u5358\u306a\u4f5c\u6210\u3092\u53ef\u80fd\u306b\u3059\u308b\u3053\u3068\u3092\u76ee\u7684\u3068\u3057\u3066\u3044\u307e\u3059\u3002\u3053\u308c\u306b\u3088\u308a\u3001HTML\u3084JSON\u3001SQL\u306e\u30af\u30a8\u30ea\u6587\u5b57\u5217\u3092\u7c21\u5358\u306b\u4f5c\u6210\u3059\u308b\u306e\u306b\u5f79\u7acb\u3061\u307e\u3059\u3002<\/p>\n<p>Java 14\u3067\u306f\u3001\u30c6\u30ad\u30b9\u30c8\u30d6\u30ed\u30c3\u30af\u306f\u307e\u3060\u30d7\u30ec\u30d3\u30e5\u30fc\u306e\u72b6\u614b\u3067\u3059\u304c\u3001\u3044\u304f\u3064\u304b\u306e\u65b0\u3057\u3044\u6a5f\u80fd\u304c\u8ffd\u52a0\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u4f7f\u7528\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<ul class=\"post-ul\">\n<li>Backslash for displaying nice-looking multiline string blocks.<\/li>\n<li>\\s is used to consider trailing spaces which are by default ignored by the compiler. It preserves all the spaces present before it.<\/li>\n<\/ul>\n<pre class=\"post-pre\"><code><span class=\"token class-name\">String<\/span> text <span class=\"token operator\">=<\/span> <span class=\"token string\">\"\"<\/span>\"\r\n                <span class=\"token class-name\">Did<\/span> you know \\\r\n                <span class=\"token class-name\">Java<\/span> <span class=\"token number\">14<\/span> \\\r\n                has the most features among\\\r\n                all non<span class=\"token operator\">-<\/span><span class=\"token constant\">LTS<\/span> versions so far\\\r\n                <span class=\"token string\">\"\"<\/span>\"<span class=\"token punctuation\">;<\/span>\r\n\r\n<span class=\"token class-name\">String<\/span> text2 <span class=\"token operator\">=<\/span> <span class=\"token triple-quoted-string string\">\"\"\"\r\n                line1\r\n                line2 \\s\r\n                line3\r\n                \"\"\"<\/span><span class=\"token punctuation\">;<\/span>\r\n\r\n\r\n<span class=\"token class-name\">String<\/span> text3 <span class=\"token operator\">=<\/span> <span class=\"token string\">\"line1\\nline2 \\nline3\\n\"<\/span>\r\n\r\n<span class=\"token comment\">\/\/text2 and text3 are equal.<\/span>\r\n<\/code><\/pre>\n<p>\u53c2\u8003\u6587\u732e: OpenJDK 14<\/p>\n","protected":false},"excerpt":{"rendered":"<p>6\u30f6\u6708\u30b5\u30a4\u30af\u30eb\u306e\u4f1d\u7d71\u3092\u5b88\u308b\u305f\u3081\u3001Java 13\u304c2019\u5e749\u670817\u65e5\u306b\u30ea\u30ea\u30fc\u30b9\u3055\u308c\u305f\u5f8c\u3001Java 14\u3001\u3082\u30461\u3064\u306e\u975eLTS\u30d0\u30fc\u30b8\u30e7\u30f3\u306f2020\u5e743\u670817\u65e5\u306b\u30ea\u30ea\u30fc\u30b9\u4e88\u5b9a\u3067\u3059\u3002 Java 14\u306e\u6a5f\u80fd \u4ee5\u4e0b\u306bJava 14\u306e [&hellip;]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[26,61],"class_list":["post-742","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-26","tag-61"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - 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