[BCEL-320] Add LruCacheClassPathRepository that can scan many JAR files without OutOfMemoryError

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 6.4.0
• Assignee: Unassigned
• Reporter: Tomo Suzuki
• Created: 17/Jun/19 12:28
• Updated: 05/Jul/19 22:59
• Resolved: 05/Jul/19 22:59

Description

(This ticket is derivation from BCEL-317, which I found creating ConstantUtf8 cache is not straightforward under current ClassPathRepository design.)

We use BCEL library in https://github.com/GoogleCloudPlatform/cloud-opensource-java . Thank you for great library.

Background

Our use of BCEL ClassPathRepository and MemorySensitiveClassPathRepository causes OutOfMemoryError when they scan many (~200) JAR files. Initially I thought this problem could be fixed by BCEL-317, but it turned out that it's not straightforward under current design. Instead of focusing on ConstantUtf8, I decided to use my own custom ClassPathRepository that uses LRU cache internally to hold JavaClass instances. It worked.

This ticket is to contribute the idea to BCEL library so that other users can benefit from it.

Test Case

This GitHub project is a example of OutOfMemoryError caused by scanning many JAR files using BCEL ClassPathRepository and MemorySensitiveClassPathRepository:

https://github.com/suztomo/bcel-oome-example

Issue Links

• links to: GitHub Pull Request #28