{"id":4291,"date":"2025-04-30T15:16:08","date_gmt":"2025-04-30T15:16:08","guid":{"rendered":"https:\/\/www.aviator.co\/blog\/?p=4291"},"modified":"2025-08-19T12:58:20","modified_gmt":"2025-08-19T12:58:20","slug":"java-version-upgrade","status":"publish","type":"post","link":"https:\/\/www.aviator.co\/blog\/java-version-upgrade\/","title":{"rendered":"Java Version Upgrade: A Hands-on Guide from Java 8 to 17"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-version-upgrade.png\" alt=\"java version upgrade\" class=\"wp-image-4293\" srcset=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-version-upgrade.png 1024w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-version-upgrade-300x169.png 300w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-version-upgrade-768x432.png 768w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">TL;DR<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Upgrading from Java 8 to 17 isn\u2019t just a version bump, it\u2019s a gateway to Java new features from 8 to 17 like <code>var<\/code>, <code>records<\/code>, and switch expressions, making code more concise, readable, and easier to maintain.<\/li>\n\n\n\n<li>The upgrade addresses compatibility gaps as modern frameworks (Spring Boot 3, JUnit 5, Micrometer) and CI\/CD tools drop support for Java 8, forcing teams to modernize to stay supported.<\/li>\n\n\n\n<li>Migration isn\u2019t trivial: removed modules (e.g., JAXB, Nashorn) and build tool upgrades (Maven\/Gradle) mean teams need to audit dependencies, update plugins, and adjust build configs (e.g., compiler plugin, toolchains).<\/li>\n\n\n\n<li>A typical workflow: prep and clean the codebase, modernize incrementally, validate with CI (GitHub Actions, Maven\/Gradle builds), test across JDKs, and deploy carefully (e.g., canary, blue-green) with rollback plans.<\/li>\n\n\n\n<li>The result: faster builds, better runtime performance, modern language benefits, and a future-proof codebase ready for the latest frameworks and tools\u2014all with reduced maintenance overhead.<\/li>\n<\/ul>\n\n\n\n<p>Upgrading Java might seem dangerous, especially if your version &#8220;just works.&#8221; But keeping Java 8 in 2025 means bypassing significant performance gains, up-to-date syntax, and extended support. Considering a <strong>Java 8 upgrade<\/strong> now will allow you to benefit from these improvements.&nbsp;<\/p>\n\n\n\n<p>Imagine you\u2019re working on a backend system built in Java 8\u2014a stable monolith that\u2019s served the business well for years. But now, CI builds drag, memory usage spikes under load, and new developers struggle to maintain legacy patterns. Meanwhile, frameworks like Spring Boot 3, JUnit 5, and observability tools such as OpenTelemetry and Micrometer no longer support Java 8. Staying put is no longer sustainable.<\/p>\n\n\n\n<p>This tutorial takes you through the what, why, and how of upgrading from Java 8 to Java 17. We delve into important language features, performance improvements, breaking changes, and migration strategies, with real code examples. Whether it&#8217;s maintaining an old code base or <strong>updating the Java version<\/strong> for your backend stack, this blog helps you to plan and implement smoothly with confidence.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Upgrading Java: The What, Why, and Now<\/strong><\/h2>\n\n\n\n<p>, It has been more than ten years now since Java 8&nbsp; launched in 2014, and whereas it\u2019s still reliable, but it\u2019s no longer the recommended default.<\/p>\n\n\n\n<p>For developers looking to upgrade, understanding the differences highlighted by a comparison of <strong>Java 8 vs Java 17<\/strong> is crucial.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>LTS Releases Give You a Safer Path Forward<\/strong><\/h3>\n\n\n\n<p>Oracle and other vendors like Azul, Amazon, and Eclipse Foundation mark certain Java versions as <strong>Long-Term Support (LTS)<\/strong>. These get security patches and updates for at least 4-8 years, making them ideal for production environments.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Java 11 <\/strong>(released in 2018) is the first LTS after Java 8, following two non-LTS releases (Java 9 and Java 10).<br><\/li>\n\n\n\n<li><strong>Java 17<\/strong> (released in 2021) is the next LTS and current go-to for many enterprises.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Modern Java Is Easier to Write<\/strong><\/h3>\n\n\n\n<p>Upgrading isn&#8217;t just about using the latest version\u2014it&#8217;s about gaining access to powerful language features, better performance, stronger security, and modern development tools that simplify code and boost productivity.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>var: Introduced in Java 10, helps reduce boilerplate in local variable declarations. It doesn&#8217;t compromise type safety\u2014it simply infers the type from the assigned value at compile time.<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>records<\/strong>: Introduced in Java 14 (preview) and finalized in Java 16, they simplify DTOs and value classes with less code and more clarity.<br><\/li>\n\n\n\n<li><strong>Sealed classes<\/strong>: Introduced in Java 17, <em>sealed classes<\/em> give you fine-grained control over inheritance by explicitly declaring which classes can extend or implement them. This helps enforce architectural boundaries and makes code easier to reason about.<\/li>\n<\/ul>\n\n\n\n<p>These modern constructs make code more expressive, compact, and maintainable.<\/p>\n\n\n\n<p>Now let&#8217;s check what the issues are with modern frameworks.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Compatibility with Modern Tooling and Frameworks<\/strong><\/h3>\n\n\n\n<p>Frameworks like <strong>Spring Boot<\/strong>, <strong>Micronaut<\/strong>, and <strong>Quarkus<\/strong> have started targeting newer Java versions for optimal performance. Many modern CI\/CD tools like Jenkins, Gitlab, testing libraries like JUnit 5, Mockito, and observability stacks like <strong>Micrometer<\/strong>, <strong>Prometheus<\/strong> drop support for Java 8 as they adopt newer JVM features.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Breaking Changes and Migration Considerations<\/strong><\/h2>\n\n\n\n<p>Upgrading from Java 8 to 17 isn&#8217;t a drop-in replacement. Understanding what\u2019s deprecated, removed, or restructured helps prevent build failures and runtime surprises.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Removed Modules That Might Break Your Build<\/strong><\/h3>\n\n\n\n<p>Java 9 introduced the <a href=\"https:\/\/www.oracle.com\/corporate\/features\/understanding-java-9-modules.html\" target=\"_blank\" rel=\"noopener nofollow\" title=\"\"><strong>Java Platform Module System (JPMS<\/strong><\/a><strong>)<\/strong>, and with it came modularization and removals.<\/p>\n\n\n\n<p>Some commonly used modules in Java 8 were either deprecated or entirely removed by Java 11:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>java.xml.bind<\/strong><strong> (JAXB)<\/strong><strong><br><\/strong> Used for XML serialization\/deserialization. Removed in Java 11.<br><em>Fix:<\/em> Add it as a separate dependency: javax.xml.bind:jaxb-api.<br><\/li>\n\n\n\n<li><strong>Nashorn JavaScript Engine<\/strong><strong><br><\/strong> Deprecated in Java 11 and removed in Java 15.<br><em>Fix:<\/em> Use alternatives like <strong>GraalVM JavaScript<\/strong> if scripting is required.<br><\/li>\n\n\n\n<li><strong>CORBA, Java EE modules (<\/strong><strong>java.activation<\/strong><strong>, <\/strong><strong>java.xml.ws<\/strong><strong>, etc.)<\/strong><strong><br><\/strong> All have been removed.<br><em>Fix:<\/em> These need external libraries now, often via Maven or Gradle.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Impact on Build Tools and Plugin Compatibility<\/strong><\/h3>\n\n\n\n<p>Your <strong>build system<\/strong> might be coupled with Java 8-specific tooling or plugin versions. Migration requires checking compatibility across your stack:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Maven<\/strong><strong><br><\/strong>\n<ul class=\"wp-block-list\">\n<li>Ensure you&#8217;re on Maven 3.8+ for full Java 17 compatibility.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p>Update compiler plugin:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;maven-compiler-plugin&gt;\n&nbsp; &lt;configuration&gt;\n&nbsp; &nbsp; &lt;release&gt;17&lt;\/release&gt;\n&nbsp; &lt;\/configuration&gt;\n&lt;\/maven-compiler-plugin&gt;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Gradle<\/strong><strong><br><\/strong>\n<ul class=\"wp-block-list\">\n<li>Use Gradle 7+ for Java 17 support.<br><\/li>\n\n\n\n<li>Update the toolchain or javaVersion block accordingly.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p>Many older plugin versions (checkstyle, spotbugs, surefire) may not support Java 17. Make sure you audit and upgrade them too.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What\u2019s New in Java 17 (Compared to Java 8)<\/strong><\/h2>\n\n\n\n<p>Upgrading from Java 8 to 17 is more than just ticking a version number, it\u2019s a leap across almost a decade of innovation. Java has evolved to make developers more productive, code more expressive, and applications more performant.<\/p>\n\n\n\n<p>Let\u2019s break down what\u2019s changed between Java 9 and 17, grouped by themes and versions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Java 9\u201311: Foundational Shifts<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-9-to-java-11.png\" alt=\"\" class=\"wp-image-4302\" srcset=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-9-to-java-11.png 1024w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-9-to-java-11-300x169.png 300w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-9-to-java-11-768x432.png 768w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Now, as we are done with the feature shits and upgrade, let\u2019s go through example for each.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Example: Using <\/strong><strong>var<\/strong><strong> to simplify verbose declarations<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ Java 8\nMap&lt;String, List&lt;Integer&gt;&gt; map = new HashMap&lt;&gt;();\n\n\/\/ Java 10+\nvar map = new HashMap&lt;String, List&lt;Integer&gt;&gt;();<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Java 12\u201314: Expressive Syntax Improvements<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-12-to-java-14.png\" alt=\"\" class=\"wp-image-4303\" srcset=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-12-to-java-14.png 1024w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-12-to-java-14-300x169.png 300w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-12-to-java-14-768x432.png 768w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p><strong>Example: Modern switch expression<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ Java 8 traditional switch statement\nint result;\nswitch (value) {\n&nbsp; case \"A\":\n&nbsp; &nbsp; result = 1; &nbsp; &nbsp; &nbsp; \/\/ Assign value for case \"A\"\n&nbsp; &nbsp; break;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; \/\/ Prevent fall-through\n&nbsp; default:\n&nbsp; &nbsp; result = 0; &nbsp; &nbsp; &nbsp; \/\/ Default case assignment\n}\n\n\/\/ Java 12+ switch expression (concise and returns a value)\nint result = switch (value) {\n&nbsp; case \"A\" -&gt; 1; &nbsp; &nbsp; &nbsp; \/\/ Directly returns 1 for case \"A\"\n&nbsp; default -&gt; 0;&nbsp; &nbsp; &nbsp; &nbsp; \/\/ Returns 0 for any other value\n};<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Java 15\u201317: Concise Models, Safer APIs<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-15-to-java17.png\" alt=\"\" class=\"wp-image-4304\" srcset=\"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-15-to-java17.png 1024w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-15-to-java17-300x169.png 300w, https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-15-to-java17-768x432.png 768w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p><strong>Example: Replacing boilerplate POJOs with Records<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ Java 8 version\npublic class User {\n&nbsp; &nbsp; \/\/ A private final field to store the user's name\n&nbsp; &nbsp; private final String name;\n\n&nbsp; &nbsp; \/\/ Constructor to initialize the name\n&nbsp; &nbsp; public User(String name) {\n&nbsp; &nbsp; &nbsp; &nbsp; this.name = name;\n&nbsp; &nbsp; }\n\n&nbsp; &nbsp; \/\/ Getter method to access the name\n&nbsp; &nbsp; public String getName() {\n&nbsp; &nbsp; &nbsp; &nbsp; return name;\n&nbsp; &nbsp; }\n}\n\n\/\/ Java 16+ version using records\n\/\/ 'record' automatically creates:\n\/\/ - private final fields\n\/\/ - constructor\n\/\/ - getters (named exactly like the field, i.e., user.name())\n\/\/ - equals(), hashCode(), and toString() methods\nrecord User(String name) {}<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Migration Workflow: Java 8 to 17<\/strong><\/h2>\n\n\n\n<p>If you&#8217;re wondering, &#8220;<strong>How do I upgrade Java<\/strong>?&#8221;, this guide is for you. Here\u2019s a step-by-step workflow you can follow to make the upgrade smooth, predictable, and safe.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Step 1: Prepare the Codebase<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Clean up old dependencies<\/strong>: Identify deprecated or Java EE modules removed in 11+.<br><\/li>\n\n\n\n<li><strong>Run static analysis<\/strong>: Use tools like <strong>SpotBugs<\/strong>, <strong>PMD<\/strong>, or <strong>SonarQube<\/strong> to catch risky constructs.<br><\/li>\n\n\n\n<li><strong>Add compiler flags<\/strong>: Configure your build tool to specify the source and target compatibility using &#8211;release or appropriate java.version.<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;!-- Maven compiler plugin example --&gt;\n&lt;configuration&gt;\n&nbsp; &lt;release&gt;8&lt;\/release&gt;\n&lt;\/configuration&gt;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Step 2: Upgrade Your Build System<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Update Maven or Gradle<\/strong> to recent versions that support Java 17 (e.g., Maven 3.8+, Gradle 7+).<br><\/li>\n\n\n\n<li><strong>Use toolchains<\/strong> to target multiple JDKs for hybrid compatibility testing.<br><\/li>\n\n\n\n<li><strong>Set cross-compilation flags<\/strong> like &#8211;release 8 to ensure Java 8 compatibility during migration.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Step 3: Modernize Gradually<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Enable error-prone or checkstyle rules<\/strong> to enforce modern Java usage patterns.<br><\/li>\n\n\n\n<li><strong>Refactor incrementally<\/strong>: Start with syntax-only upgrades like text blocks or var declarations.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Example:<\/strong><\/h3>\n\n\n\n<p><strong>Before (Java 8):<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>String json = \"{\\n\" +\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; \"&nbsp; \\\"name\\\": \\\"Ainan\\\",\\n\" +\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; \"&nbsp; \\\"role\\\": \\\"Developer\\\"\\n\" +\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; \"}\";<\/code><\/pre>\n\n\n\n<p><strong>After (Java 15+ with Text Blocks):<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>String json = \"\"\"\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; \"name\": \"Ainan\",\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; \"role\": \"Developer\"\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; \"\"\";<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Test each feature<\/strong> in isolation, avoid sweeping refactors.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Step 4: Validate Compatibility<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Test builds across JDKs<\/strong> (8, 11, and 17) using CI.<br><\/li>\n\n\n\n<li><strong>Run <\/strong><strong>jdeps<\/strong> to find the modules your code depends on.<br><\/li>\n\n\n\n<li><strong>Profile runtime behavior<\/strong> using <strong>Java Flight Recorder<\/strong> (JFR) to catch regressions.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Step 5: Deploying with Java 17<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Use Canary or Blue-Green deployments<\/strong> to test with a small subset of traffic first.<br><\/li>\n\n\n\n<li><strong>Implement rollback strategies<\/strong> with Docker containers or JDK isolation.<br><\/li>\n\n\n\n<li><strong>Monitor performance and error logs<\/strong> closely during rollout.<\/li>\n<\/ul>\n\n\n\n<p>Now let\u2019s go through the example migration setup.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Example Of Migration Setup as per the Workflow<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Migrating a Spring Boot App from Java 8 to 17<\/strong><\/h3>\n\n\n\n<p>To bring a Spring Boot project up to Java 17, a few strategic updates are needed, starting with your build configuration and environment setup.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>pom.xml<\/strong><strong> Changes (Maven Toolchain Support)<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;properties&gt;\n&nbsp; &lt;maven.compiler.release&gt;17&lt;\/maven.compiler.release&gt;\n&lt;\/properties&gt;\n\n&lt;build&gt;\n&nbsp; &lt;plugins&gt;\n&nbsp; &nbsp; &lt;plugin&gt;\n&nbsp; &nbsp; &nbsp; &lt;groupId&gt;org.apache.maven.plugins&lt;\/groupId&gt;\n&nbsp; &nbsp; &nbsp; &lt;artifactId&gt;maven-toolchains-plugin&lt;\/artifactId&gt;\n&nbsp; &nbsp; &nbsp; &lt;version&gt;3.1.1&lt;\/version&gt;\n&nbsp; &nbsp; &nbsp; &lt;executions&gt;\n&nbsp; &nbsp; &nbsp; &nbsp; &lt;execution&gt;\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;goals&gt;\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;goal&gt;toolchain&lt;\/goal&gt;\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;\/goals&gt;\n&nbsp; &nbsp; &nbsp; &nbsp; &lt;\/execution&gt;\n&nbsp; &nbsp; &nbsp; &lt;\/executions&gt;\n&nbsp; &nbsp; &lt;\/plugin&gt;\n&nbsp; &lt;\/plugins&gt;\n&lt;\/build&gt;<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Setting Up JDK 17 in a Dockerfile<\/strong><\/h4>\n\n\n\n<p>Use the official Eclipse Temurin base image to containerize your app with Java 17:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>FROM eclipse-temurin:17-jdk\nWORKDIR \/app\nCOPY . .\nRUN .\/mvnw clean install\nCMD &#91;\"java\", \"-jar\", \"target\/app.jar\"]<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>GitHub Actions for Java 17<\/strong><\/h4>\n\n\n\n<p>Automate your builds and tests with Java 17 support:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>jobs:\n&nbsp; build:\n&nbsp; &nbsp; runs-on: ubuntu-latest\n&nbsp; &nbsp; steps:\n&nbsp; &nbsp; &nbsp; - uses: actions\/checkout@v2\n&nbsp; &nbsp; &nbsp; - name: Set up JDK 17\n&nbsp; &nbsp; &nbsp; &nbsp; uses: actions\/setup-java@v3\n&nbsp; &nbsp; &nbsp; &nbsp; with:\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; java-version: '17'\n&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; distribution: 'temurin'\n&nbsp; &nbsp; &nbsp; - run: .\/mvnw clean test<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>JVM Tuning for ZGC or G1<\/strong><\/h4>\n\n\n\n<p>Update your startup script:<\/p>\n\n\n\n<p>ZGC offers ultra-low pause times, ideal for latency-sensitive services:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>java -XX:+UseZGC -Xms512m -Xmx2g -jar app.jar<\/code><\/pre>\n\n\n\n<p>Or for G1 (default in JDK 9+):<\/p>\n\n\n\n<p>G1 is a balanced collector with predictable pauses:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>java -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -jar app.jar<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Testing Modern Features<\/strong><\/h3>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Records to Reduce Boilerplate<\/strong><\/h4>\n\n\n\n<p>Records auto-generate constructors, getters, and more:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ Old Java 8 style\npublic class Person {\n&nbsp; private final String name;\n&nbsp; public Person(String name) { this.name = name; }\n&nbsp; public String getName() { return name; }\n}\n\n\/\/ Java 17 record\nrecord Person(String name) {}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Pattern Matching with <\/strong><strong>instanceof<\/strong><\/h4>\n\n\n\n<p>No more redundant casting:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ Java 8\nif (obj instanceof String) {\n&nbsp; String s = (String) obj;\n&nbsp; System.out.println(s.toUpperCase());\n}\n\n\/\/ Java 17\nif (obj instanceof String s) {\n&nbsp; System.out.println(s.toUpperCase());\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Switch Expressions<\/strong><\/h4>\n\n\n\n<p>More expressive, less error-prone:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ Java 8\nString result;\nswitch (status) {\n&nbsp; case \"START\": result = \"begin\"; break;\n&nbsp; case \"STOP\": result = \"end\"; break;\n&nbsp; default: result = \"unknown\";\n}\n\n\/\/ Java 17\nString result = switch (status) {\n&nbsp; case \"START\" -&gt; \"begin\";\n&nbsp; case \"STOP\" -&gt; \"end\";\n&nbsp; default -&gt; \"unknown\";\n};<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Conclusion<\/strong><\/h2>\n\n\n\n<p>Upgrading to Java 17 from Java 8 is a wise move, bringing long-term advantages. You receive better security, performance, and a much more expressive language. But most importantly, you future-proof your applications with LTS support and compatibility with new frameworks and tools.<\/p>\n\n\n\n<p>Whether you\u2019re migrating a microservice or a monolith, breaking the upgrade into manageable steps helps avoid risk while embracing all the goodness Java has picked up in the last decade.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>FAQs<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1. Why upgrade from Java 8 to 17?<\/strong><\/h3>\n\n\n\n<p>Upgrading from Java 8 to Java 17 delivers performance enhancements, new language capabilities, and enhanced tooling support. It&#8217;s a strategic upgrade that promises stability and long-term growth.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>2. What is the difference between Java 8 and Java 17?<\/strong><\/h3>\n\n\n\n<p>Considering the <strong>difference between Java 8 and Java 17<\/strong>, Java 17 has features like var, records, text blocks, sealed classes, enhanced garbage collection (ZGC, G1), new APIs, and removal of legacy modules. It is leaner, faster, and simpler to maintain than Java 8.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>3. Which Java version is faster?<\/strong><\/h3>\n\n\n\n<p>Each successive release of Java improves performance, but Java 17 is faster than Java 8 because there are smarter JIT optimizations, better memory management, and better garbage collection. Java 21 and 22 continue the trend, and Java 24 (which comes out now) takes it up a notch.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>4. Which Java version is better, 17 or 21?<\/strong><\/h3>\n\n\n\n<p>Both are great, but Java 17 is an LTS release and thus the safer default for enterprise environments. Java 21 is also an LTS and includes more recent features like virtual threads. Choose based on your support needs and plan.<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Learn why upgrading from Java 8 to 17 matters in 2025, and how to do it right with new features, better performance, and modern tool support.<\/p>\n","protected":false},"author":38,"featured_media":4293,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[302],"tags":[272,271],"class_list":["post-4291","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tooling-integrations"],"blocksy_meta":[],"acf":[],"aioseo_notices":[],"jetpack_featured_media_url":"https:\/\/www.aviator.co\/blog\/wp-content\/uploads\/2025\/04\/java-version-upgrade.png","post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/posts\/4291","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/users\/38"}],"replies":[{"embeddable":true,"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/comments?post=4291"}],"version-history":[{"count":7,"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/posts\/4291\/revisions"}],"predecessor-version":[{"id":4701,"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/posts\/4291\/revisions\/4701"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/media\/4293"}],"wp:attachment":[{"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/media?parent=4291"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/categories?post=4291"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.aviator.co\/blog\/wp-json\/wp\/v2\/tags?post=4291"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}