# YARN DIRECTORY LAYOUT Hadoop Yarn related codes are organized in separate directories to minimize duplicated code. * common : Common codes that do not depending on specific version of Hadoop. * alpha / stable : Codes that involve specific version of Hadoop YARN API. alpha represents 0.23 and 2.0.x stable represents 2.2 and later, until the API changes again. alpha / stable will build together with common dir into a single jar