Mockito 5.3.1 High Memory Usage

[debraj-manna]

With mock 5.3.1 I am observing a high usage of heap memory. Looking at the heap dump it looks like most of the memory are being taken by a Map containing MockMethodInterceptor.

I am not that familiar with the internal implementation of Mockito. Can someone please suggest what could be going wrong here or are there any known issue in the version of Mockito I am using?

[TimvdLippe]

Does this happen since 5.3.1 or does it happen before? Can you also test out several ByteBuddy versions to see if there is a regression with ByteBuddy instead?

[debraj-manna]

Looks like the byte-buddy that is getting used in our codebase is 1.12.23 from the dependency tree

org.mockito:mockito-core:jar:5.3.1:test
[INFO] |  |  \- net.bytebuddy:byte-buddy-agent:jar:1.12.23:test

Mockito has specified version 1.14.4 of byte-buddy. I will try using the byte-buddy of 1.14.4 or you suggest trying some other version?

[debraj-spotnana]

@TimvdLippe I tried with version 1.14.4 and 1.14.14 version of byte-buddy. With both versions, I am observing the same behavior as 1.12.23.

Is there a way for me to not use byte-buddy with mockito?

[TimvdLippe]

You can bisect if a previous version of Mockito has similar behavior. In case (for example) 4.9 does not show the same behavior, it means there is a regression in Mockito instead. If there is a difference in behavior, you can try to use mockito-subclass. If you don't want any of the pre-built mockmakers, you can implement the MockMaker interface yourself, but I want to warn you that it is tricky to implement correctly.

[debraj-spotnana]

@TimvdLippe It looks like the same issue is reported in the quarkus project also. There using mockito-subclass solved the issue.

quarkusio/quarkus#31251

In some places we are mocking static methods, if I am going to use mockito-subclass with mockito 5.3.1, how do I mock the static methods?

[debraj-manna]

In my case also adding Mockito.framework().clearInlineMocks() solved the issue as mentioned in quarkusio/quarkus#31251