Describe a difficult bug you fixed in an Android app.

Choose a bug that needed investigation, and describe the method.

Strong scenarios:

• A crash affecting only some devices or one manufacturer, found through Crashlytics stack traces and device breakdown.
• A memory leak — an Activity retained by a static reference, a listener never unregistered, or an inner class holding an implicit reference to its outer Activity. LeakCanary and the Android Studio Memory Profiler are the tools.
• An ANR caused by work on the main thread — a database query, a large JSON parse, or disk I/O.
• A configuration change bug where state was lost on rotation or after process death.
• A race condition in asynchronous code that only appeared on slow networks.

How to tell it: how you reproduced it (usually the hardest part), how you narrowed it down, the tools you used, the root cause, and the regression test or structural change that prevents recurrence.

Note: Process death is an excellent thing to mention. Testing with "Don't keep activities" enabled in developer options simulates it, and a large share of Android state bugs only appear that way — most candidates have never tried it.