networking - GrindLoop: Android & iOS Interview Prep

Why Reading the Response Body in an OkHttp Interceptor Throws IllegalStateException: closed

October 4, 2026 by Arsam

Close-up of exception-handling code on a screen, illustrating IllegalStateException: closed in an OkHttp interceptor

Reading the response body in an OkHttp interceptor causes IllegalStateException: closed. The two stacked causes, the peekBody fix and the interview answer.

Why Offline Sync Duplicates Records After a Retry

October 1, 2026 by Arsam

A smartphone lying face up on a white table, illustrating offline sync duplicates after a retry

Offline sync duplicates records when a retried POST can’t prove it’s a retry. The two stacked bugs, a runnable Kotlin repro, the fix and the interview answer.

Why Gson Returns Null Fields Only in Your Release Build

September 28, 2026 by Arsam

Code editor on a dark monitor showing JSON parsing code, illustrating Gson null fields in an Android release build

A Kotlin data class parsed by Gson works in debug and comes back null in release. Here’s the two-bug reason (R8 plus Gson skipping your constructor), the fix, and the interview answer.

Why viewModelScope.async Swallows a Failed API Call

September 27, 2026September 22, 2026 by Arsam

Network server rack with blinking status lights and ethernet cables, representing an async API call over the network

A viewModelScope async call that nobody awaits hides its failure completely. Why a root async stores the exception, why the same code inside launch crashes instead, a runnable repro and the fix.