[OPENEJB-1265] TempClassLoader buffer reuse reduces memory requirements

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Implemented
• Affects Version/s: 3.1.x
• Fix Version/s: 4.7.0
• Component/s: server
• Labels: OpenEJB TempClassLoader
• Environment: All
• Assignee: Unassigned
• Reporter: Andy Gumbrecht
• Created: 27/Apr/10 07:21
• Updated: 02/Jul/14 17:44
• Resolved: 06/Dec/12 16:06

Description

The current TempClassLoader potentially uses a new 8k ByteArrayOutputStream per class that it inspects.
Whilst hunting for a possible ClassLoader issue I found that replacing the ByteArrayOutputStream with a reusable one leads to a substantial reduction in memory during server start up.

I am unable to quantify what 'substantial' means in real terms as I have not run any real benchmarking, but it is fair to say that I had noticed heap sizes growing to over 180m during a server start compared to the 90m that I have now. These values would be application specific, but it would be nice to see if this is an improvement for others.

I have also synchronized a few access methods to ensure that resources are protected during the inspection process.