—This paper reports on a study mining the exception stack traces included in 159,048 issues reported on Android projects hosted in GitHub (482 projects) and Google Code (157 projects). The goal of this study is to investigate whether stack trace information can reveal bug hazards related to exception handling code that may lead to a decrease in application robustness. Overall 6,005 exception stack traces were extracted, and subjected to source code and bytecode analysis. The outcomes of this study include the identification of the following bug hazards: (i) unexpected cross-type exception wrappings (for instance, trying to handle an instance of OutOfMemoryError “hidden” in a checked exception) which can make the exceptionrelated code more complex and negatively impact the application robustness; (ii) undocumented runtime exceptions thrown by both the Android platform and third party libraries; and (iii) undocumented checked exceptions thrown by the Android Platform. Such undocum...