org.apache.hadoop.fs
Interfaces 
PathFilter
PositionedReadable
Seekable
Syncable
Classes 
BlockLocation
BufferedFSInputStream
ChecksumFileSystem
ContentSummary
DF
DU
FileStatus
FileSystem
FileSystem.Statistics
FileUtil
FileUtil.HardLink
FilterFileSystem
FSDataInputStream
FSDataOutputStream
FSInputChecker
FSInputStream
FSOutputSummer
FsShell
FsUrlStreamHandlerFactory
HarFileSystem
InMemoryFileSystem
LocalDirAllocator
LocalFileSystem
Path
RawLocalFileSystem
ShellCommand
Trash
Exceptions 
ChecksumException
Errors 
FSError