org.apache.hadoop.dfs
Interfaces 
FSConstants
Classes 
DataNode
DatanodeID
DatanodeInfo
DFSAdmin
DFSck
DistributedFileSystem
JspHelper
NameNode
NamenodeFsck
StreamFile
Enums 
DatanodeInfo.AdminStates
FSConstants.DecommissionAction
FSConstants.SafeModeAction
Exceptions 
AlreadyBeingCreatedException
LeaseExpiredException
NotReplicatedYetException
SafeModeException