Major Description
FileContext.getLocalFSFileContext() instantiates a FileContext object upon the first call to it, and for all subsequent calls returns back that instance (a static localFsSingleton object). With security turned on, this causes some hard-to-debug situations when that fileContext is used for doing HDFS operations. This is because the UserGroupInformation is stored when a FileContext is instantiated. If the process in question wishes to use different UserGroupInformation objects for different file system operations (where the corresponding FileContext objects are obtained via calls to FileContext.getLocalFSFileContext()), it doesn't work.