Possible leak using Guice about guice

[mcculls]

The generated glue held inside that ClassValue should be unloaded when the host class (ie. the application class) is unloaded, which is when its class-loader is able to be unloaded. I can double-check with a simple test app, but it sounds like something else is keeping your child class-loaders alive, which then keeps those generated fast-classes alive.

Is your code publicly available?

Note if you don't need bytecode generation then you can turn it off with:

-Dguice_bytecode_gen_option=DISABLED

but that would also mean you couldn't do method interception.

[lucianoRM]

Sorry, the code is not public.

The only strong references I am seeing are from Guice. But, maybe once the weak/soft references are cleaned, since Guice's references will be the only ones, they will be cleaned as well? I could check that.

In which scenario would we be using method interception?

We only have a bunch of Modules either binding Interfaces to Implementations (in the configure() method) or defining a @ Provides method.

As for injection, we do field and constructor injection with @ Inject

[mcculls]

Part of the problem with unloading is that a lot is held back until the class-loader itself becomes unloadable, which does make it hard to debug - we do have tests in the codebase to verify proxy unloading, which uses a similar mechanism, and those are currently passing.

Regarding method interception - that's if you are using the bindInterceptor method: https://github.com/google/guice/wiki/AOP

If you're not using that then try adding -Dguice_bytecode_gen_option=DISABLED as a JVM option to see if it helps.

[lucianoRM]

Awesome! I will try to figure out if there is anything else preventing the Class Loader to be unloaded.

In the meantime, I will try using that flag, I don't think I require method interception. Maybe I can isolate the root problem better.

Thanks for the quick response!

[lucianoRM]

Following up on this

Using -Dguice_bytecode_gen_option=DISABLED definitely worked. I no longer see those paths to GC roots. What's more, the service seems to be working just fine, so I guess we can execute without method interception.

However, based on the information you provided, even if using bytecode generation, those paths should be cleared. So, I will keep searching for another cause for this issue. I already have a lead with a lib we are using.

Closing this ticket for now.

Thanks a lot for the help!