This document discusses using data mining techniques to improve software maintenance and reliability. It provides an overview of applying techniques like classification, association rule mining, and clustering to mine software engineering data from code bases, change histories, and bug reports. Specifically, it describes mining frequent patterns and rules from source code and revision histories to detect bugs as deviations from these patterns. A methodology is presented that involves parsing source code to build an itemset database, applying frequent itemset mining to extract programming patterns and rules, and detecting violations of rules as potential bugs. Challenges and limitations of these approaches are also discussed.