org.apache.hadoop.io
Interfaces 
Closeable
SequenceFile.Sorter.RawKeyValueIterator
SequenceFile.ValueBytes
Writable
WritableComparable
WritableFactory
Classes 
ArrayFile
ArrayFile.Reader
ArrayFile.Writer
ArrayWritable
BooleanWritable
BooleanWritable.Comparator
BytesWritable
BytesWritable.Comparator
CompressedWritable
DataInputBuffer
DataOutputBuffer
FloatWritable
FloatWritable.Comparator
GenericWritable
IntWritable
IntWritable.Comparator
LongWritable
LongWritable.Comparator
LongWritable.DecreasingComparator
MapFile
MapFile.Reader
MapFile.Writer
MD5Hash
MD5Hash.Comparator
NullWritable
ObjectWritable
SequenceFile
SequenceFile.Reader
SequenceFile.Sorter
SequenceFile.Writer
SetFile
SetFile.Reader
SetFile.Writer
Text
Text.Comparator
TwoDArrayWritable
UTF8
UTF8.Comparator
VersionedWritable
WritableComparator
WritableFactories
WritableName
WritableUtils
Enums 
SequenceFile.CompressionType
Exceptions 
VersionMismatchException