Memory leak in ModelBatch.render()

While profiling my Android application I have noticed that every frame the number of allocated objects is increasing (see the white line on the screenshot below).

Issue details

Preliminary investigation has shown that every call of ModelBatch.render() creates an instance of ArrayList iterator.

As I understand, while there is a forEach() call, Iterable<T> create the iterator on every call, every frame.

for (final RenderableProvider renderableProvider : renderableProviders)
     render(renderableProvider, environment);

I know there is a flag Collections.allocateIterators which could be a reason for that (by default it is “false”, which is good). Even when I have set it to “false” explicitly, it did not help.

Reproduction steps/code

My code which call the render is quite trivial:

modelBatch.begin(camera)
modelBatch.render(modelList1, environment) // modelList1 - ArrayList<ModelInstance>
modelBatch.render(modelList2, environment) // modelList2 - ArrayList<ModelInstance>
modelBatch.end()

Version of LibGDX and/or relevant dependencies

gdxVersion = ‘1.9.10’ roboVMVersion = ‘2.3.8’ box2DLightsVersion = ‘1.4’ ashleyVersion = ‘1.7.0’ aiVersion = ‘1.8.0’

KotlinVersion = “1.3.72” Java version = “1.8.0_251”

Stacktrace

iterator:806, ArrayList (java.util)
render:272, ModelBatch (com.badlogic.gdx.graphics.g3d)
render:76, MySceneRenderer (com.mysupergame.game.ui)
...

Please select the affected platforms

I have experienced that for Android platform, and did not check for others, assuming it is not related to the platform.

[obigu]

The memory issue you describe is not a memory leak nor the problem is in the render() implementation. Use an Iterable implementation that doesn’t allocate by making modelList a com.badlogic.gdx.utils.Array instead of a java.uitil.ArrayList.

[JackRainy]

@obigu , thank you for the advice using the com.badlogic.gdx.utils.Array instead of java.uitil.ArrayList. It has helped. Now I would say it is an imperfection of ArrayList implementation. Anyway, it is not related to render() method now. I close the issue.