org.apache.commons.collections
Interfaces 
Bag
Buffer
Closure
Factory
MultiMap
Predicate
PriorityQueue
SortedBag
Transformer
Classes 
ArrayEnumeration
ArrayIterator
ArrayStack
BagUtils
BeanMap
BinaryHeap
BoundedFifoBuffer
BufferUtils
CollectionUtils
ComparatorUtils
CursorableLinkedList
DefaultMapBag
DefaultMapEntry
DoubleOrderedMap
EnumerationIterator
ExtendedProperties
FastArrayList
FastHashMap
FastTreeMap
FilterIterator
FilterListIterator
HashBag
IteratorEnumeration
IteratorUtils
ListUtils
LRUMap
MapUtils
MultiHashMap
ProxyIterator
ProxyListIterator
ProxyMap
ReferenceMap
SequencedHashMap
SetUtils
SingletonIterator
SoftRefHashMap
StaticBucketMap
StringStack
SynchronizedPriorityQueue
TransformIterator
TreeBag
UnboundedFifoBuffer
Exceptions 
BufferOverflowException
BufferUnderflowException