1. I bet you have a memory leak
Nikita Salnikov-Tarnovski
@iNikem
Saturday, June 29, 13

2. Plumbr
• We solve memory leaks ... for now
• Giving you the exact location of the leak with enough
information to fix it
• The foundation is based on machine learning
• Ongoing effort
Saturday, June 29, 13

3. Plumbr
• trained on 1,000,000 memory snapshots
• From 5,000 different applications
• Finding 88% of the existing leaks.
• 30,000 monthly unique visitors on our site
• 500 monthly downloads
• 2600+ leaks discovered
Saturday, June 29, 13

4. Memory leak
• A situation where some objects are not used by
application any more, but GC fails to recognize them as
unused
• The notion of “object is not used by application any
more” is totally, absolutely, 100% application specific!
http://plumbr.eu/blog/what-is-a-memory-leak
Saturday, June 29, 13

5. Classloader leak
• The most common leak in web applications
• If even 1 class is left behind, he keeps all his friends
• After some redeploys, you crash
Saturday, June 29, 13

6. Should you care?
• PermGen will die soon
• Metaspace do not eliminate the problem
• No redeploy, no problem
• Yeah, but...
Saturday, June 29, 13

7. Boy scout rule
Saturday, June 29, 13

8. The problem is...
• Most of the classloader leaks you will ever encounter
are not your fault
• Libraries
• You have no idea what do you use in your application
Saturday, June 29, 13

9. Demo
• Quite simple web application
• CRUD with JPA, Spring, JSP, WebSockets
• Running on Jetty
Saturday, June 29, 13

10. Solving performance problems is hard. We don’t think it needs to be.
Saturday, June 29, 13