In a nutshell...
● ...15,409 commits made by 311 contributors
● ...representing 800,490 lines of code
● ...mostly written in Java
● ...has a well established, mature codebase
● ...maintained by a very large development team
● ...with stable Y-O-Y commits
● ...took an estimated 222 years of effort (COCOMO model)
● ...starting with its first commit in April, 2007 (>10 years old!)
Source https://www.openhub.net/p/hbase
