Using StrictMode penaltyListener/OnVmViolationListener prevents InstanceCountViolation (from setClassInstanceLimit) to be triggered. I have found this to be true for all applicable Android versions, API 28 - API 35 Beta 3. penaltyListener was introduced in API 28.

This is problematic because penaltyListener is essential these days for filtering endless numbers of false positive StrictMode detections from Android framework and libraries when those detections are enabled. (E.g. NonSdkApiUsedViolation)

Essentially this means that one can either detect InstanceCountViolation or all other violations, but not both.

Minimal repro available here: https://github.com/bubenheimer/strictmodeclassinstancelimit

Here's the gist of it:

val executor = Executors.newSingleThreadExecutor()

StrictMode.setVmPolicy(
    StrictMode.VmPolicy.Builder()
        .setClassInstanceLimit(Application::class.java, 0)
        .penaltyListener(executor, OnVmViolationListener)
        .build()
)

The repro sets an (invalid) class instance limit of 0 for android.app.Application in MainActivity.kt.

By default the repro has OnVmViolationListener set and no Violation will be logged. Comment out the penaltyListener() line to unset the listener, at which point the app will log InstanceCountViolation, as expected:

StrictMode policy violation: android.os.strictmode.InstanceCountViolation: class android.app.Application; instances=1; limit=0
    at android.os.StrictMode.setClassInstanceLimit(StrictMode.java:1)

I've reproduced this behavior on all emulator versions from API 28-35. I've also reproduced it on Samsung Galaxy S21 with OneUI 6.1.

Issue 348683481

Links (7)

Issue metadata