JVM settings > 4GB memory store produce a Confluence crash when rendering PDF files with large images.
Steps to reproduce:
1. Configure a Confluence instance with > 4GB of memory
2. Attach Medusa.pdf to a page and embed it in a ViewFile macro
3. Save the page and Confluence will crawl to a halt and crash
Possible Workaround one of customers reported that upgrading java to version 7u55 stabilised the instance from the occurrence of crashes.