--- title: What is Context Switching? - Cracking the Java Coding... description: Context switching occurs when an OS pauses a running thread to execute another, saving and restoring all thread state (code, data, registers, cache). This... canonical: https://daily.dev/posts/what-is-context-switching---cracking-the-java-coding-interview-javacoding-javatips-0zlyh1oum twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: What is Context Switching? - Cracking the Java Coding Interview #javacoding #javatips | daily.dev og:description: Context switching occurs when an OS pauses a running thread to execute another, saving and restoring all thread state (code, data, registers, cache). This... og:url: https://daily.dev/posts/what-is-context-switching---cracking-the-java-coding-interview-javacoding-javatips-0zlyh1oum og:image: https://api.daily.dev/og/posts/0ZLyH1OUm.png og:image:alt: What is Context Switching? - Cracking the Java Coding Interview #javacoding #javatips 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. # What is Context Switching? - Cracking the Java Coding Interview #javacoding #javatips **[Java \(Official Oracle\)](https://daily.dev/sources/java-oracle)** · 1 min read · 2 upvotes · 0 comments ## Summary Context switching occurs when an OS pauses a running thread to execute another, saving and restoring all thread state (code, data, registers, cache). This costs around 400 microseconds per switch and can significantly hurt application performance. It commonly happens when a kernel thread blocks on a network call. Java's virtual threads help mitigate this issue because blocking a virtual thread does not block the underlying kernel thread, reducing unnecessary context switches. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is context switching and why does it hurt application performance? Context switching is when the operating system pauses a running thread to let another thread run, removing that thread's code, data, and state from the CPU core's cache and registers so it can be restored later. This operation takes roughly 400 microseconds, which is costly when it happens frequently, such as when a kernel thread blocks waiting on a network call. _daily.dev surfaces concurrency deep dives for developers optimizing thread performance in Java._ ### How do virtual threads in Java help avoid context switching problems? Virtual threads help because blocking a virtual thread does not block the underlying kernel thread that runs it, so the expensive context switch of a kernel thread does not occur. This removes a common source of performance bugs where kernel threads waiting on I/O, like network calls, trigger costly switches taking around 400 microseconds each. _Developers weighing virtual threads for I/O-heavy Java apps can find deeper explainers on daily.dev._ ## Similar posts on daily.dev - [Context Switches](https://daily.dev/posts/context-switches-3g5ft7ffm) · matklad · 1 upvotes · 0 comments - [Aesthetics of Single Threading](https://daily.dev/posts/aesthetics-of-single-threading-ywtpquehu) · Hacker News · 4 upvotes · 1 comments - [Kernel Context Switch Costs And Spin Locks In Perf Profile: A Practical Study](https://daily.dev/posts/kernel-context-switch-costs-and-spin-locks-in-perf-profile-a-practical-study-joukt6jgh) · ITNEXT · 0 upvotes · 0 comments --- Tags: [#java](https://daily.dev/tags/java) [View this post on daily.dev](https://daily.dev/posts/what-is-context-switching---cracking-the-java-coding-interview-javacoding-javatips-0zlyh1oum) ```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":"What is Context Switching? - Cracking the Java Coding Interview #javacoding #javatips","url":"https://daily.dev/posts/what-is-context-switching---cracking-the-java-coding-interview-javacoding-javatips-0zlyh1oum","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/what-is-context-switching---cracking-the-java-coding-interview-javacoding-javatips-0zlyh1oum"},"datePublished":"2026-07-10T10:22:48.029Z","dateModified":"2026-09-14T07:49:39.397Z","description":"Context switching occurs when an OS pauses a running thread to execute another, saving and restoring all thread state (code, data, registers, cache). 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