Skip to content

Commit 8f63543

Browse files
brunoborgesCopilot
brunoborges
and
Copilot
committed
Initial release of java.evolved
85 side-by-side Java code comparisons (Java 8 → Java 25). Static site for GitHub Pages at javaevolved.github.io. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
0 parents  commit 8f63543

File tree

93 files changed

+34749
-0
lines changed

Some content is hidden

Large Commits have some content hidden by default. Use the searchbox below for content that may be hidden.

93 files changed

+34749
-0
lines changed

‎aot-class-preloading.html‎

Lines changed: 314 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,314 @@
1+
<!DOCTYPE html>
2+
<html lang="en">
3+
<head>
4+
<meta charset="UTF-8">
5+
<meta name="viewport" content="width=device-width, initial-scale=1.0">
6+
<title>AOT class preloading | java.evolved</title>
7+
<meta name="description" content="Cache class loading and compilation for instant startup.">
8+
<meta name="robots" content="index, follow">
9+
<link rel="canonical" href="https://javaevolved.github.io/aot-class-preloading.html">
10+
<link rel="stylesheet" href="styles.css">
11+
<link rel="icon" href="favicon.svg" type="image/svg+xml">
12+
<link rel="manifest" href="manifest.json">
13+
<meta name="theme-color" content="#f97316">
14+
<meta name="mobile-web-app-capable" content="yes">
15+
<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
16+
<meta name="apple-mobile-web-app-title" content="java.evolved">
17+
18+
<meta property="og:title" content="AOT class preloading | java.evolved">
19+
<meta property="og:description" content="Cache class loading and compilation for instant startup.">
20+
<meta property="og:url" content="https://javaevolved.github.io/aot-class-preloading.html">
21+
<meta property="og:type" content="article">
22+
<meta property="og:site_name" content="java.evolved">
23+
<meta property="og:locale" content="en_US">
24+
25+
<meta name="twitter:card" content="summary">
26+
<meta name="twitter:title" content="AOT class preloading | java.evolved">
27+
<meta name="twitter:description" content="Cache class loading and compilation for instant startup.">
28+
29+
<script type="application/ld+json">
30+
{
31+
"@context": "https://schema.org",
32+
"@type": "TechArticle",
33+
"headline": "AOT class preloading",
34+
"description": "Cache class loading and compilation for instant startup.",
35+
"url": "https://javaevolved.github.io/aot-class-preloading.html",
36+
"publisher": {
37+
"@type": "Organization",
38+
"name": "java.evolved",
39+
"url": "https://javaevolved.github.io"
40+
},
41+
"mainEntityOfPage": {
42+
"@type": "WebPage",
43+
"@id": "https://javaevolved.github.io/aot-class-preloading.html"
44+
}
45+
}
46+
</script>
47+
<script type="application/ld+json">
48+
{
49+
"@context": "https://schema.org",
50+
"@type": "BreadcrumbList",
51+
"itemListElement": [
52+
{
53+
"@type": "ListItem",
54+
"position": 1,
55+
"name": "Home",
56+
"item": "https://javaevolved.github.io/"
57+
},
58+
{
59+
"@type": "ListItem",
60+
"position": 2,
61+
"name": "Tooling",
62+
"item": "https://javaevolved.github.io/?cat=tooling"
63+
},
64+
{
65+
"@type": "ListItem",
66+
"position": 3,
67+
"name": "AOT class preloading"
68+
}
69+
]
70+
}
71+
</script>
72+
</head>
73+
<body data-page="single">
74+
<nav>
75+
<div class="nav-inner">
76+
<a href="/" class="logo">java.<span>evolved</span></a>
77+
<div class="nav-right">
78+
<a href="/" class="back-link">← All patterns</a>
79+
80+
<div class="nav-arrows">
81+
<a href="/compact-object-headers.html" aria-label="Previous pattern">←</a>
82+
83+
</div>
84+
</div>
85+
</div>
86+
</nav>
87+
88+
<article class="article">
89+
<div class="breadcrumb">
90+
<a href="/">Home</a>
91+
<span class="sep">/</span>
92+
<a href="/?cat=tooling">Tooling</a>
93+
<span class="sep">/</span>
94+
<span>AOT class preloading</span>
95+
</div>
96+
97+
<div class="tip-header">
98+
<div class="tip-meta">
99+
<span class="badge tooling">Tooling</span>
100+
<span class="badge advanced">advanced</span>
101+
</div>
102+
<h1>AOT class preloading</h1>
103+
<p>Cache class loading and compilation for instant startup.</p>
104+
</div>
105+
106+
<section class="compare-section">
107+
<div class="section-label">Code Comparison</div>
108+
<div class="compare-container">
109+
<div class="compare-panel old-panel">
110+
<div class="compare-panel-header">
111+
<span class="compare-tag old">✕ Java 8</span>
112+
<button class="copy-btn" data-code="old">Copy</button>
113+
</div>
114+
<div class="compare-code">
115+
<pre class="code-text">// Every startup:
116+
// - Load 10,000+ classes
117+
// - Verify bytecode
118+
// - JIT compile hot paths
119+
// Startup: 2-5 seconds</pre>
120+
</div>
121+
</div>
122+
<div class="compare-panel modern-panel">
123+
<div class="compare-panel-header">
124+
<span class="compare-tag modern">✓ Java 25</span>
125+
<button class="copy-btn" data-code="modern">Copy</button>
126+
</div>
127+
<div class="compare-code">
128+
<pre class="code-text">// Training run:
129+
$ java -XX:AOTMode=record \
130+
-XX:AOTConfiguration=app.aotconf \
131+
-cp app.jar com.App
132+
// Production:
133+
$ java -XX:AOTMode=on \
134+
-XX:AOTCache=app.aot \
135+
-cp app.jar com.App</pre>
136+
</div>
137+
</div>
138+
</div>
139+
</section>
140+
141+
<section class="why-section">
142+
<div class="section-label">Why the modern way wins</div>
143+
<div class="why-grid">
144+
<div class="why-card">
145+
<div class="why-icon">⚡</div>
146+
<h3>Faster startup</h3>
147+
<p>Skip class loading, verification, and linking.</p>
148+
</div>
149+
<div class="why-card">
150+
<div class="why-icon">📦</div>
151+
<h3>Cached state</h3>
152+
<p>Training run captures the ideal class state.</p>
153+
</div>
154+
<div class="why-card">
155+
<div class="why-icon">🔧</div>
156+
<h3>No code changes</h3>
157+
<p>Works with existing applications — just add JVM flags.</p>
158+
</div>
159+
</div>
160+
</section>
161+
162+
<div class="info-grid">
163+
<div class="info-card">
164+
<div class="info-label">Old Approach</div>
165+
<div class="info-value red">Cold Start Every Time</div>
166+
</div>
167+
<div class="info-card">
168+
<div class="info-label">Modern Approach</div>
169+
<div class="info-value green">AOT Cache</div>
170+
</div>
171+
<div class="info-card">
172+
<div class="info-label">Since JDK</div>
173+
<div class="info-value accent">25</div>
174+
</div>
175+
<div class="info-card">
176+
<div class="info-label">Difficulty</div>
177+
<div class="info-value blue">advanced</div>
178+
</div>
179+
</div>
180+
181+
<section class="bs-section">
182+
<div class="section-label">JDK Support</div>
183+
<div class="bs-card">
184+
<div class="bs-feature-name">AOT class preloading</div>
185+
<span class="baseline-badge widely">Available</span>
186+
<p class="bs-desc">Available in JDK 25 LTS (JEPs 514/515, Sept 2025). Experimental.</p>
187+
</div>
188+
</section>
189+
190+
<section class="explanation">
191+
<h2>How it works</h2>
192+
<p>AOT class preloading caches loaded and linked classes from a training run. On subsequent starts, classes are loaded from the cache, skipping verification and linking. Combined with AOT compilation, this dramatically reduces startup time.</p>
193+
</section>
194+
195+
<section class="related">
196+
<h2>Related patterns</h2>
197+
<div class="related-grid">
198+
<a href="/jshell-prototyping.html" class="tip-card">
199+
<div class="tip-card-body">
200+
<div class="tip-card-header">
201+
<div class="tip-badges">
202+
<span class="badge tooling">Tooling</span>
203+
<span class="badge beginner">beginner</span>
204+
</div>
205+
</div>
206+
<h3>JShell for prototyping</h3>
207+
</div>
208+
<div class="card-code">
209+
<div class="card-code-layer old-layer">
210+
<div class="mini-label">Java 8</div>
211+
<pre class="code-text">// 1. Create Test.java
212+
// 2. javac Test.java
213+
// 3. java Test
214+
// Just to test one expression!</pre>
215+
</div>
216+
<div class="card-code-layer modern-layer">
217+
<div class="mini-label">Java 9+</div>
218+
<pre class="code-text">$ jshell
219+
jshell&gt; &quot;hello&quot;.chars().count()
220+
$1 ==&gt; 5
221+
jshell&gt; List.of(1,2,3).reversed()
222+
$2 ==&gt; [3, 2, 1]</pre>
223+
</div>
224+
<span class="hover-hint">Hover to see modern ➜</span>
225+
</div>
226+
<div class="tip-card-footer">
227+
<span class="browser-support"><span class="dot"></span>JDK 9+</span>
228+
<span class="arrow-link">→</span>
229+
</div>
230+
</a>
231+
<a href="/single-file-execution.html" class="tip-card">
232+
<div class="tip-card-body">
233+
<div class="tip-card-header">
234+
<div class="tip-badges">
235+
<span class="badge tooling">Tooling</span>
236+
<span class="badge beginner">beginner</span>
237+
</div>
238+
</div>
239+
<h3>Single-file execution</h3>
240+
</div>
241+
<div class="card-code">
242+
<div class="card-code-layer old-layer">
243+
<div class="mini-label">Java 8</div>
244+
<pre class="code-text">$ javac HelloWorld.java
245+
$ java HelloWorld
246+
// Two steps every time</pre>
247+
</div>
248+
<div class="card-code-layer modern-layer">
249+
<div class="mini-label">Java 11+</div>
250+
<pre class="code-text">$ java HelloWorld.java
251+
// Compiles and runs in one step
252+
// Also works with shebangs:
253+
#!/usr/bin/java --source 25</pre>
254+
</div>
255+
<span class="hover-hint">Hover to see modern ➜</span>
256+
</div>
257+
<div class="tip-card-footer">
258+
<span class="browser-support"><span class="dot"></span>JDK 11+</span>
259+
<span class="arrow-link">→</span>
260+
</div>
261+
</a>
262+
<a href="/multi-file-source.html" class="tip-card">
263+
<div class="tip-card-body">
264+
<div class="tip-card-header">
265+
<div class="tip-badges">
266+
<span class="badge tooling">Tooling</span>
267+
<span class="badge intermediate">intermediate</span>
268+
</div>
269+
</div>
270+
<h3>Multi-file source launcher</h3>
271+
</div>
272+
<div class="card-code">
273+
<div class="card-code-layer old-layer">
274+
<div class="mini-label">Java 8</div>
275+
<pre class="code-text">$ javac *.java
276+
$ java Main
277+
// Must compile all files first
278+
// Need a build tool for dependencies</pre>
279+
</div>
280+
<div class="card-code-layer modern-layer">
281+
<div class="mini-label">Java 22+</div>
282+
<pre class="code-text">$ java Main.java
283+
// Automatically finds and compiles
284+
// other source files referenced
285+
// by Main.java</pre>
286+
</div>
287+
<span class="hover-hint">Hover to see modern ➜</span>
288+
</div>
289+
<div class="tip-card-footer">
290+
<span class="browser-support"><span class="dot"></span>JDK 22+</span>
291+
<span class="arrow-link">→</span>
292+
</div>
293+
</a>
294+
</div>
295+
</section>
296+
</article>
297+
</section>
298+
299+
300+
<div class="social-share">
301+
<span class="share-label">Share</span>
302+
<a href="https://x.com/intent/tweet?url=https%3A%2F%2Fjavaevolved.github.io%2Faot-class-preloading.html&text=AOT%20class%20preloading%20%E2%80%93%20java.evolved" target="_blank" rel="noopener" class="share-btn share-x" aria-label="Share on X">𝕏</a>
303+
<a href="https://bsky.app/intent/compose?text=AOT%20class%20preloading%20%E2%80%93%20java.evolved%20https%3A%2F%2Fjavaevolved.github.io%2Faot-class-preloading.html" target="_blank" rel="noopener" class="share-btn share-bsky" aria-label="Share on Bluesky">🦋</a>
304+
<a href="https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fjavaevolved.github.io%2Faot-class-preloading.html" target="_blank" rel="noopener" class="share-btn share-li" aria-label="Share on LinkedIn">in</a>
305+
<a href="https://www.reddit.com/submit?url=https%3A%2F%2Fjavaevolved.github.io%2Faot-class-preloading.html&title=AOT%20class%20preloading%20%E2%80%93%20java.evolved" target="_blank" rel="noopener" class="share-btn share-reddit" aria-label="Share on Reddit">⬡</a>
306+
</div>
307+
308+
<footer>
309+
<p>A project by <a href="https://github.com/brunoborges" target="_blank" rel="noopener">Bruno Borges</a></p>
310+
</footer>
311+
312+
<script src="app.js"></script>
313+
</body>
314+
</html>

0 commit comments

Comments
 (0)