Claude Code performance

Memory Leak in Long-Running Background Job

A background job that runs periodically starts consuming more memory with each execution. After hours of running, the application runs out of memory and crashes. The job itself is correct but something isn't being cleaned up properly.

Memory usage climbs steadily despite the job appearing to complete normally.

Error Messages You Might See

java.lang.OutOfMemoryError: Java heap space Memory usage climbs to 100% after running job repeatedly Process killed due to memory limit exceeded
java.lang.OutOfMemoryError: Java heap spaceMemory usage climbs to 100% after running job repeatedlyProcess killed due to memory limit exceeded

Common Causes

  1. Large collection (List, Set) accumulating items without clearing
  2. Event listeners registered but never unregistered, accumulating with each run
  3. Database connections or file handles not closed in finally block
  4. Strong references held to completed objects preventing garbage collection
  5. Timer or scheduled task not cancelled, creating new instances on top of old ones

How to Fix It

Use memory profiler to find memory growth (Java: JProfiler, YourKit). Look for accumulating collections. Ensure resources are closed with try-finally or try-with-resources. Unregister event listeners when done. Clear collections: list.clear(). Check for circular references. Use weak references if needed. Monitor memory: jmap -heap PID

Real developers can help you.

Stanislav Prigodich Stanislav Prigodich 15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it. Daniel Vázquez Daniel Vázquez Software Engineer with over 10 years of experience on Startups, Government, big tech industry & consulting. Omar Faruk Omar Faruk As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience. My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture. I played a key role in creating a scalable and maintainable platform to support educators and learners globally. I'm enthusiastic about embracing new challenges and making meaningful contributions. Meïr Ankri Meïr Ankri Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews. Victor Denisov Victor Denisov Developer Matthew Jordan Matthew Jordan I've been working at a large software company named Kainos for 2 years, and mainly specialise in Platform Engineering. I regularly enjoy working on software products outside of work, and I'm a huge fan of game development using Unity. I personally enjoy Python & C# in my spare time, but I also specialise in multiple different platform-related technologies from my day job. Krishna Sai Kuncha Krishna Sai Kuncha Experienced Professional Full stack Developer with 8+ years of experience across react, python, js, ts, golang and react-native. Developed inhouse websearch tooling for AI before websearch was solved : ) ISHANTDEEP SINGH ISHANTDEEP SINGH Senior Software Engineer with 7+ years of experience in React, JavaScript, TypeScript, Next.js, and Node.js. I’ve also worked as a tech lead for startups, owning end-to-end technical execution including architecture, development, scaling, and delivery. I bring a strong mix of hands-on coding, product thinking, and technical leadership, and I’m comfortable building products from scratch as well as improving and scaling existing systems. Tejas Chokhawala Tejas Chokhawala Full-stack engineer with 5 years experience building production web apps using React, Next.js and TypeScript. Focused on performance, clean architecture and shipping fast. Experienced with Supabase/Postgres backends, Stripe billing, and building AI-assisted developer tools. Taufan Taufan I’m a product-focused engineer and tech leader who builds scalable systems and turns ideas into production-ready platforms. Over the past years, I’ve worked across startups and fast-moving teams, leading backend architecture, improving system reliability, and shipping products used by thousands of users. My strength is not just writing code — but connecting product vision, technical execution, and business impact.

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Frequently Asked Questions

How to find memory leaks?

Use profiler (JProfiler, YourKit, Chrome DevTools). Take heap dumps before/after memory growth. Compare objects in memory.

How to fix common memory leaks?

Use try-finally for resource cleanup. Unregister listeners: obj.removeEventListener(). Clear collections before reuse: list.clear(). Use weak references for caches.

What's a proper resource cleanup pattern?

try-with-resources (Java 7+): try (Resource r = new Resource()) { use r } (auto-closes). Or try-finally with cleanup in finally block.

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