| 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. | 
| java.util.concurrent.atomic | A small toolkit of classes that support lock-free thread-safe
 programming on single variables. | 
| java.util.stream | Classes to support functional-style operations on streams of elements, such
 as map-reduce transformations on collections. | 
| Modifier and Type | Method and Description | 
|---|---|
| static void | Arrays. parallelPrefix(long[] array,
              int fromIndex,
              int toIndex,
              LongBinaryOperator op)Performs  Arrays.parallelPrefix(long[], LongBinaryOperator)for the given subrange of the array. | 
| static void | Arrays. parallelPrefix(long[] array,
              LongBinaryOperator op)Cumulates, in parallel, each element of the given array in place,
 using the supplied function. | 
| Modifier and Type | Method and Description | 
|---|---|
| long | ConcurrentHashMap. reduceEntriesToLong(long parallelismThreshold,
                   ToLongFunction<Map.Entry<K,V>> transformer,
                   long basis,
                   LongBinaryOperator reducer)Returns the result of accumulating the given transformation
 of all entries using the given reducer to combine values,
 and the given basis as an identity value. | 
| long | ConcurrentHashMap. reduceKeysToLong(long parallelismThreshold,
                ToLongFunction<? super K> transformer,
                long basis,
                LongBinaryOperator reducer)Returns the result of accumulating the given transformation
 of all keys using the given reducer to combine values, and
 the given basis as an identity value. | 
| long | ConcurrentHashMap. reduceToLong(long parallelismThreshold,
            ToLongBiFunction<? super K,? super V> transformer,
            long basis,
            LongBinaryOperator reducer)Returns the result of accumulating the given transformation
 of all (key, value) pairs using the given reducer to
 combine values, and the given basis as an identity value. | 
| long | ConcurrentHashMap. reduceValuesToLong(long parallelismThreshold,
                  ToLongFunction<? super V> transformer,
                  long basis,
                  LongBinaryOperator reducer)Returns the result of accumulating the given transformation
 of all values using the given reducer to combine values,
 and the given basis as an identity value. | 
| Modifier and Type | Method and Description | 
|---|---|
| long | AtomicLongArray. accumulateAndGet(int i,
                long x,
                LongBinaryOperator accumulatorFunction)Atomically updates the element at index  iwith the
 results of applying the given function to the current and
 given values, returning the updated value. | 
| long | AtomicLong. accumulateAndGet(long x,
                LongBinaryOperator accumulatorFunction)Atomically updates the current value with the results of
 applying the given function to the current and given values,
 returning the updated value. | 
| long | AtomicLongFieldUpdater. accumulateAndGet(T obj,
                long x,
                LongBinaryOperator accumulatorFunction)Atomically updates the field of the given object managed by this
 updater with the results of applying the given function to the
 current and given values, returning the updated value. | 
| long | AtomicLongArray. getAndAccumulate(int i,
                long x,
                LongBinaryOperator accumulatorFunction)Atomically updates the element at index  iwith the
 results of applying the given function to the current and
 given values, returning the previous value. | 
| long | AtomicLong. getAndAccumulate(long x,
                LongBinaryOperator accumulatorFunction)Atomically updates the current value with the results of
 applying the given function to the current and given values,
 returning the previous value. | 
| long | AtomicLongFieldUpdater. getAndAccumulate(T obj,
                long x,
                LongBinaryOperator accumulatorFunction)Atomically updates the field of the given object managed by this
 updater with the results of applying the given function to the
 current and given values, returning the previous value. | 
| Constructor and Description | 
|---|
| LongAccumulator(LongBinaryOperator accumulatorFunction,
               long identity)Creates a new instance using the given accumulator function
 and identity element. | 
| Modifier and Type | Method and Description | 
|---|---|
| OptionalLong | LongStream. reduce(LongBinaryOperator op)Performs a reduction on the
 elements of this stream, using an
 associative accumulation
 function, and returns an  OptionalLongdescribing the reduced value,
 if any. | 
| long | LongStream. reduce(long identity,
      LongBinaryOperator op)Performs a reduction on the
 elements of this stream, using the provided identity value and an
 associative
 accumulation function, and returns the reduced value. | 
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