I was new to Android development back then. One of the project requirements was to implement a feature, that will prevent the users from turning off the phone. Even if the users tries to turn off, the phone shouldn't turn off (specially when the phone battery is sealed). So, I tried a method and it works! But later the users reported that the feature doesn't work! I mean, I can clearly see that the feature works in all the phones I have ever tested. But later I realized that the feature worked in Debug APK but not in Release APK. I mean, seriously? It's not even some kind of pro-guard issues that happens with GSON+Parcelable. So, I did it again using a new method. Again, it works in Debug but not in Release. After trying and failing multiple times, finally I found a solution! May be this bug alone took me almost a week to fix it!