# Package org.apache.tomcat.util.collections

Class Summary
CaseInsensitiveKeyMap<V>: A Map implementation that uses case-insensitive (using `Locale.ENGLISH`) strings as keys.
ConcurrentCache<K,​V>
ManagedConcurrentWeakHashMap<K,​V>: Concurrent hash map that holds its keys via weak references.
SynchronizedQueue<T>: This is intended as a (mostly) GC-free alternative to `ConcurrentLinkedQueue` when the requirement is to create an unbounded queue with no requirement to shrink the queue.
SynchronizedStack<T>: This is intended as a (mostly) GC-free alternative to `Stack` when the requirement is to create a pool of re-usable objects with no requirement to shrink the pool.