--- title: Crosswalk and its JS, JAVA and Native Extensions performance description: An exploration of Crosswalk-android's extension system, specifically how to bundle native (.so) libraries inside an APK and call them via Java extensions from... canonical: https://daily.dev/posts/crosswalk-and-its-js-java-and-native-extensions-performance-2qnb8buqv twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Crosswalk and its JS, JAVA and Native Extensions performance | daily.dev og:description: An exploration of Crosswalk-android's extension system, specifically how to bundle native (.so) libraries inside an APK and call them via Java extensions from... og:url: https://daily.dev/posts/crosswalk-and-its-js-java-and-native-extensions-performance-2qnb8buqv og:image: https://api.daily.dev/og/posts/2Qnb8BuqV.png og:image:alt: Crosswalk and its JS, JAVA and Native Extensions performance og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Crosswalk and its JS, JAVA and Native Extensions performance **[Collabora Blog](https://daily.dev/sources/collabora)** · 4 min read · 0 upvotes · 0 comments ## Summary An exploration of Crosswalk-android's extension system, specifically how to bundle native (.so) libraries inside an APK and call them via Java extensions from JavaScript. Performance benchmarks compare JS, Java, and native C code using prime-finding and summation algorithms. Key findings: JS-to-Java or JS-to-Java-to-C context switching costs roughly 1ms per call, making native extensions slower for trivial operations. For compute-heavy tasks (50K element summation), native code is ~3x faster than JavaScript, as V8's smart optimizations (e.g., modulus tricks) don't apply. The takeaway: measure before optimizing, and avoid native calls inside tight loops. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the performance cost of calling a native extension from JavaScript in Crosswalk-android? The JS-to-Java or JS-to-Java-to-C context switch in Crosswalk-android costs just under 1ms per call. For small operations like summing 10 elements, this overhead makes native calls slower than pure JavaScript. For compute-heavy tasks like summing 50,000 elements, native code is roughly 3x faster than JavaScript, since V8's smart optimizations no longer close the gap. _Developers weighing hybrid app architecture trade-offs like this track Crosswalk and WebView performance discussions on daily.dev._ ### How do I include a native .so library inside a Crosswalk-android extension APK? Add a copy step in the ant build.xml recipe between the unjar and jar tasks, placing the .so file into the correct ABI directory inside the extension package. For example: . This takes advantage of the extension JAR being opened and closed to include the META-INF, injecting the native library at the same time. _Android developers bundling native code into hybrid apps find related build and packaging discussions on daily.dev._ ## Similar posts on daily.dev - [We Didn't Want to Build Another Java Server](https://daily.dev/posts/we-didn-t-want-to-build-another-java-server-rji0itet1) · Foojay.io · 20 upvotes · 0 comments - [Clojure is almost as fast as C \(with some help\)](https://daily.dev/posts/clojure-is-almost-as-fast-as-c-with-some-help--faibfofkn) · Lobsters · 0 upvotes · 0 comments - [WebAssembly vs. JavaScript: Testing Side-by-Side Performance](https://daily.dev/posts/webassembly-vs-javascript-testing-side-by-side-performance-uai1ulk0u) · The New Stack · 0 upvotes · 0 comments - [Java Is Fast. Your Code Might Not Be.](https://daily.dev/posts/java-is-fast-your-code-might-not-be--melyfth7m) · Hacker News · 0 upvotes · 0 comments --- Tags: [#javascript](https://daily.dev/tags/javascript), [#performance](https://daily.dev/tags/performance), [#android](https://daily.dev/tags/android) [View this post on daily.dev](https://daily.dev/posts/crosswalk-and-its-js-java-and-native-extensions-performance-2qnb8buqv) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Crosswalk and its JS, JAVA and Native Extensions performance","url":"https://daily.dev/posts/crosswalk-and-its-js-java-and-native-extensions-performance-2qnb8buqv","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/crosswalk-and-its-js-java-and-native-extensions-performance-2qnb8buqv"},"datePublished":"2026-08-11T08:55:49.672Z","dateModified":"2026-08-11T09:37:20.972Z","description":"An exploration of Crosswalk-android's extension system, specifically how to bundle native (.so) libraries inside an APK and call them via Java extensions from...","image":"https://media.daily.dev/image/upload/s--VDukGCjf--/f_auto/v1722860399/public/Placeholder%2002","thumbnailUrl":"https://media.daily.dev/image/upload/s--VDukGCjf--/f_auto/v1722860399/public/Placeholder%2002","isAccessibleForFree":true,"articleSection":"Collabora Blog","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Collabora Blog","logo":"https://media.daily.dev/image/upload/s--ZGZ0FjqS--/f_auto,q_auto/v1786438306/logos/collabora?_a=BAMAMicg0","url":"https://daily.dev/sources/collabora"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/crosswalk-and-its-js-java-and-native-extensions-performance-2qnb8buqv","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"javascript,performance,android","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Collabora Blog","item":"https://daily.dev/sources/collabora"},{"@type":"ListItem","position":3,"name":"Crosswalk and its JS, JAVA and Native Extensions performance"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/crosswalk-and-its-js-java-and-native-extensions-performance-2qnb8buqv#faq","mainEntity":[{"@type":"Question","name":"What is the performance cost of calling a native extension from JavaScript in Crosswalk-android?","acceptedAnswer":{"@type":"Answer","text":"The JS-to-Java or JS-to-Java-to-C context switch in Crosswalk-android costs just under 1ms per call. 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