Android has become the most popular OS because of its user-friendly environment, free-ware licensing and hundreds of thousands of available applications. It is an open source for contributors and developers, therefor the largest challenge it’s facing is to report, track, manage and fix the bugs generated by any code segment by the contributors. Sometimes fixing one bug can generate many other bugs; therefor code change management is also as critical task as bug tracking. We have investigated all available pervious history of android bug reports and code changes to identify bug introducing changes. For this purpose we extracted 1011 sample code changes from 208 commits and 947 different files from android project. In initial investigation of these code segments we found that 68% bugs generated and fixed in java files and rest 32% belongs to C files. Further in depth investigation exposed that 34% code changes involved ‘IF’ conditions which is the most error prone programming construct involved in the bug introducing changes. As for as the bug pattern are concerned it is the nested ‘If(){if()}’ which is mostly involved in buggy changes. Use of ‘for’ loops with ‘if’ statement also shown a good enough share in the sampled code changes. This study will help the reviewers, contributors, developers and quality assurance testers to concentrate and take special care while making or accepting changes to those constructs where it is most likely to induce a bug, which will lead to improve the quality of services provided by Android platform, and ultimately will get more satisfied users. Key Words:Android, Project, Mining Bug,Patterns.