ResponseEntity objects are accumulated in ConcurrentReferenceHashMap

[KangChanSong]

Affects: 5.2.8

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First of all, sorry for my bad english. If you're hard to understand my sentence, please comment

Ive been testing my team's project and monitoring it with scouter APM.

And found that "used heap" keeps going high whenever I call an different API .

I debugged and found that Spring accumulates ResponseEntity in ConcurrentReferenceHashMap of ResolvableType.cache.

It puts the whole response body of each ResponseEntity in ConcurrentReferenceHashMap which is static.

I believe that the Spring developers intended it for some reasons but I cannot find any even if I googled a lot.

If It it's an issue , please fix this.
if it's not, I would very appreciate you for giving me some explanation why Spring accumulates the ResponseEntity objects
even if it has a BIG BIG body.

Thank you.
Best Regard.

[snicoll]

@KangChanSong the cache that you mention is a cache of resolvable types. ResolvableType does not have a link to ResponseEntity so I am afraid I don't understand the report. Can you point to the code that you believe is caching ResponseEntity objects?

[KangChanSong]

This is a stack trace where ResponseEntity object is cached in to ConcurrentReferenceHashMap

And another screenshot of a ResponseEntity object and its incoming reference tree

[snicoll]

I can see that we have a MethodParameter implementation, ReturnValueMethodParameter, that keeps a reference to the actual return value. Spring HATEOAS seems to be using ResolvableType#forMethodParameter passing the actual MethodParameter implementation.

If the type is using MethodParameterTypeProvider I can see how that could have the side effect of keeping the return value in the cache there.

[jhoeller]

Indeed, and ReturnValueMethodParameter does not even do anything with the value itself, just obtaining the return value type on demand. Let's change this to a ReturnTypeMethodParameter that just holds on to the pre-determined value type.