| Package | Description | 
|---|---|
| java.util | Contains the collections framework, legacy collection classes, event model,
date and time facilities, internationalization, and miscellaneous utility
classes (a string tokenizer, a random-number generator, and a bit array). | 
| java.util.concurrent | Utility classes commonly useful in concurrent programming. | 
| Modifier and Type | Interface and Description | 
|---|---|
| interface  | Deque<E>A linear collection that supports element insertion and removal at
 both ends. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | AbstractQueue<E>This class provides skeletal implementations of some  Queueoperations. | 
| class  | ArrayDeque<E>Resizable-array implementation of the  Dequeinterface. | 
| class  | LinkedList<E>Doubly-linked list implementation of the  ListandDequeinterfaces. | 
| class  | PriorityQueue<E>An unbounded priority queue based on a priority heap. | 
| Modifier and Type | Method and Description | 
|---|---|
| static <T> Queue<T> | Collections. asLifoQueue(Deque<T> deque) | 
| static <E> Queue<E> | Collections. checkedQueue(Queue<E> queue,
            Class<E> type)Returns a dynamically typesafe view of the specified queue. | 
| Modifier and Type | Method and Description | 
|---|---|
| static <E> Queue<E> | Collections. checkedQueue(Queue<E> queue,
            Class<E> type)Returns a dynamically typesafe view of the specified queue. | 
| Modifier and Type | Interface and Description | 
|---|---|
| interface  | BlockingDeque<E>A  Dequethat additionally supports blocking operations that wait
 for the deque to become non-empty when retrieving an element, and wait for
 space to become available in the deque when storing an element. | 
| interface  | BlockingQueue<E>A  Queuethat additionally supports operations
 that wait for the queue to become non-empty when retrieving an
 element, and wait for space to become available in the queue when
 storing an element. | 
| interface  | TransferQueue<E>A  BlockingQueuein which producers may wait for consumers
 to receive elements. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | ArrayBlockingQueue<E>A bounded blocking queue backed by an
 array. | 
| class  | ConcurrentLinkedDeque<E>An unbounded concurrent deque based on linked nodes. | 
| class  | ConcurrentLinkedQueue<E>An unbounded thread-safe queue based on linked nodes. | 
| class  | DelayQueue<E extends Delayed>An unbounded blocking queue of
  Delayedelements, in which an element can only be taken
 when its delay has expired. | 
| class  | LinkedBlockingDeque<E>An optionally-bounded blocking deque based on
 linked nodes. | 
| class  | LinkedBlockingQueue<E>An optionally-bounded blocking queue based on
 linked nodes. | 
| class  | LinkedTransferQueue<E>An unbounded  TransferQueuebased on linked nodes. | 
| class  | PriorityBlockingQueue<E>An unbounded blocking queue that uses
 the same ordering rules as class  PriorityQueueand supplies
 blocking retrieval operations. | 
| class  | SynchronousQueue<E>A blocking queue in which each insert
 operation must wait for a corresponding remove operation by another
 thread, and vice versa. | 
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