Abstract
In software engineering, bug reports describe software bugs. Developers find the solutions of bugs through reproducing the abnormal behaviors and analyzing the source codes to find the causes of such behaviors, and thereby fix the bugs accordingly. This way of fixing bugs is tiresome and slow when done manually. The developers need to have an automated system to help them by suggesting potential solutions for bugs. However, bug reports usually contain unstructured data which make the automatic analysis of bugs difficult. This paper presents a review covering the techniques and approaches in bug localization based on a bug report with a special focus of the approaches that use crowdsourcing available in Stack Overflow forum to assist developers.