[Bug] Skywalking-java-agent SWDescriptionStrategy causes memory leaks

[hyhyf]

Search before asking

• I had searched in the issues and found no similar issues.

Apache SkyWalking Component

Java Agent (apache/skywalking-java)

What happened

I used the nashorn script engine for stress testing in my project. After running continuously for 2 hours, SWTypeDescriptionWrapper occupied more than 90% of the memory, and the old GC was frequently.

What you expected to happen

When dynamic class creation methods are used, they are put into the type cache. If this operation is repeated indefinitely, it will form a large collection that cannot be garbage collected, thereby consuming memory resources.

How to reproduce

Jdk: 1.8
Java agent: 9.2.0
Excute scripts using nashorn script engine

Anything else

No response

Are you willing to submit a pull request to fix on your own?

• Yes I am willing to submit a pull request on my own!

Code of Conduct

• I agree to follow this project's Code of Conduct

[wu-sheng]

We don't support unlimited dynamic classes. I think this is the current case. And I don't see any reason to do this in product env.

[hyhyf]

You're right, but I think someone will face the same problem as me in the future.

[wu-sheng]

Yes, maybe, but there is no proper solution for that.

[gaojingyuan001]

I’ve encountered the same issue. In my case, the script execution creates different class loaders based on the business logic to load and run scripts. When the number of custom class loaders increases, it causes a memory leak in SWDescriptionStrategy.

[kylixs]

I will work on this issue.

[kylixs]

@gaojingyuan001 @hyhyf Could you please help test this PR apache/skywalking-java#772 ? Looking forward to hearing from you.