android - GrindLoop: Android & iOS Interview Prep

String.format Locale Bug: Why “1234,50” Throws NumberFormatException on Android

October 9, 2026 by Arsam

Calculator on euro banknotes, illustrating a String.format locale bug in an Android checkout amount

A String.format locale bug turns 1234.50 into 1234,50 or Arabic digits, so toDouble() throws NumberFormatException. Runnable repro, fix and interview answer.

Does Taking a Hint in a Coding Interview Count Against You?

October 9, 2026 by Hass

Two light bulbs on a table, one lit, for a post on taking a hint in a coding interview

A hint in a coding interview costs points by its size. How the hint ladder works, when to ask for help and a full script for asking and recovering.

Why Your “Why Do You Want to Work Here” Answer Could Be About Any Company

October 8, 2026 by Sara

Sunlit home office desk with a laptop and bookshelves, where a candidate prepares a why do you want to work here answer

Your why do you want to work here answer fails if it could go to any company. Build it from one real detail, your own work and a gap. Full Android sample.

Kotlin Mutex withLock Deadlock: Why a Nested withLock Hangs Forever

October 8, 2026 by Arsam

Rusty padlock hanging from a chain, illustrating a Mutex withLock deadlock in Kotlin coroutines

A Mutex withLock deadlock comes from a non-reentrant Mutex locked twice, and it hangs with no ANR or exception. A runnable repro, the fix and wrong answers.

How to Reapply After a Failed Interview When the Recruiter Gives No Feedback

October 8, 2026 by Hass

Blank notebook, pencil and phone on a white desk, for planning how to reapply after a failed interview

How to reapply after a failed interview: get the date and the weak round from your recruiter, practice that round, then write back. Script and sample email.

Tell Me About a Time You Mentored Someone: Answering Without a Formal Mentee

October 7, 2026 by Sara

Handwritten notes and sticky notes beside a laptop, prepping to answer tell me about a time you mentored someone

How to answer tell me about a time you mentored someone without a formal mentee title: show what they did without you. A full Android sample answer.

LaunchedEffect Stale Value: Why LaunchedEffect(Unit) Calls an Old Callback

October 7, 2026 by Arsam

Hourglass running out, like a question timer hit by a LaunchedEffect stale value bug

A LaunchedEffect stale value comes from LaunchedEffect(Unit) keeping its first lambda and a captured String. Why keying on the callback fails, and the fix.

Taking the CodeSignal General Coding Assessment? Your First Score Follows You

October 7, 2026 by Hass

Laptop with a code editor on a desk, ready for a CodeSignal General Coding Assessment

Your CodeSignal General Coding Assessment score can be shared with later companies, and retakes are capped. When to test, how it scores, and a sample plan.

How to Answer the Worst Manager Interview Question Without Badmouthing Anyone

October 6, 2026 by Sara

Blank sticky notes next to a keyboard, for a post on the worst manager interview question

How to answer the worst manager interview question: describe a practice, not a person, name its cost and what you did. A full Android sample answer.

StateFlow Not Emitting When You Add to a MutableList Inside update {}

October 6, 2026 by Arsam

Miniature shopping cart and paper bag, illustrating a StateFlow not emitting when a cart item is added

StateFlow not emitting after you add to a MutableList? copy() shares the list so states compare equal, and update {} retries repeat the add. Repro and fix.