| Package | Description | 
|---|---|
| java.util.concurrent | 
 Utility classes commonly useful in concurrent programming. 
 | 
| java.util.stream | 
 Classes to support functional-style operations on streams of elements, such
 as map-reduce transformations on collections. 
 | 
| Modifier and Type | Interface and Description | 
|---|---|
interface  | 
ConcurrentNavigableMap<K,V>
A  
ConcurrentMap supporting NavigableMap operations,
 and recursively so for its navigable sub-maps. | 
| Modifier and Type | Class and Description | 
|---|---|
class  | 
ConcurrentHashMap<K,V>
A hash table supporting full concurrency of retrievals and
 high expected concurrency for updates. 
 | 
class  | 
ConcurrentSkipListMap<K,V>
A scalable concurrent  
ConcurrentNavigableMap implementation. | 
| Modifier and Type | Method and Description | 
|---|---|
static <T,K,A,D,M extends ConcurrentMap<K,D>> | 
Collectors.groupingByConcurrent(Function<? super T,? extends K> classifier,
                    Supplier<M> mapFactory,
                    Collector<? super T,A,D> downstream)
Returns a concurrent  
Collector implementing a cascaded "group by"
 operation on input elements of type T, grouping elements
 according to a classification function, and then performing a reduction
 operation on the values associated with a given key using the specified
 downstream Collector. | 
static <T,K,U,M extends ConcurrentMap<K,U>> | 
Collectors.toConcurrentMap(Function<? super T,? extends K> keyMapper,
               Function<? super T,? extends U> valueMapper,
               BinaryOperator<U> mergeFunction,
               Supplier<M> mapSupplier)
Returns a concurrent  
Collector that accumulates elements into a
 ConcurrentMap whose keys and values are the result of applying
 the provided mapping functions to the input elements. | 
| Modifier and Type | Method and Description | 
|---|---|
static <T,K> Collector<T,?,ConcurrentMap<K,List<T>>> | 
Collectors.groupingByConcurrent(Function<? super T,? extends K> classifier)
Returns a concurrent  
Collector implementing a "group by"
 operation on input elements of type T, grouping elements
 according to a classification function. | 
static <T,K,A,D> Collector<T,?,ConcurrentMap<K,D>> | 
Collectors.groupingByConcurrent(Function<? super T,? extends K> classifier,
                    Collector<? super T,A,D> downstream)
Returns a concurrent  
Collector implementing a cascaded "group by"
 operation on input elements of type T, grouping elements
 according to a classification function, and then performing a reduction
 operation on the values associated with a given key using the specified
 downstream Collector. | 
static <T,K,U> Collector<T,?,ConcurrentMap<K,U>> | 
Collectors.toConcurrentMap(Function<? super T,? extends K> keyMapper,
               Function<? super T,? extends U> valueMapper)
Returns a concurrent  
Collector that accumulates elements into a
 ConcurrentMap whose keys and values are the result of applying
 the provided mapping functions to the input elements. | 
static <T,K,U> Collector<T,?,ConcurrentMap<K,U>> | 
Collectors.toConcurrentMap(Function<? super T,? extends K> keyMapper,
               Function<? super T,? extends U> valueMapper,
               BinaryOperator<U> mergeFunction)
Returns a concurrent  
Collector that accumulates elements into a
 ConcurrentMap whose keys and values are the result of applying
 the provided mapping functions to the input elements. | 
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