org.apache.poi.util
Interfaces 
FixedField
LittleEndianConsts
Classes 
BinaryTree
BitField
BlockingInputStream
ByteField
CommonsLogger
DrawingDump
HexDump
HexRead
IntegerField
IntList
IOUtils
LittleEndian
LongField
NullLogger
POILogFactory
POILogger
ShortField
ShortList
StringUtil
SystemOutLogger
Exceptions 
LittleEndian.BufferUnderrunException