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TypeManager.CreateProxy does not cache constructor reflection #7479
Description
Activity
I can still see this in a recent .NET MAUI app:
It looks like any API that returns a new instance of a Java.Lang.Object subclass would look up the constructor again.
- First call, Java object A: looks up constructor
- Second call, Java object A: already has a C# object, reuses object, doesn't call constructor at all
- Third call, Java object B: looks up constructor again
I think this could happen for commonly called APIs like
View.Backgroundthat return uniqueDrawableinstances. MAUI calls these a lot.- added a commit that references this issue
on Aug 12, 2026 - locked and limited conversation to collaborators
on Sep 12, 2026
Android application type
Android for .NET (net6.0-android, etc.)
Affected platform version
.NET 6 and 7
Description
The following piece of code is very expensive when manipulating native objects:
https://github.com/xamarin/xamarin-android/blob/91669a4e489104668fdd07382e40cf070aa559ac/src/Mono.Android/Java.Interop/TypeManager.cs#L327-L348
As there is no caching for getting constructors, in the worst case, twice:
Steps to Reproduce
Get
ShapeDrawable.Paintin a loop.Did you find any workaround?
None.
Relevant log output
No response