Creating an Optional The Optional<T> class models the absence of a value by a special singleton returned by the Optional.empty()…
Mapping Adapter for Downstream Collectors The mapping() method of the Collectors class encapsulates a mapper function and a downstream collector…
Collecting to an Array The overloaded method toArray() can be used to collect or accumulate into an array. It is…
Numeric Optional Classes An instance of the generic Optional<T> class can only encapsulate an object. To deal with optional numeric…
Matching Elements The match operations determine whether any, all, or none of the stream elements satisfy a given Predicate. These…
16.7 Terminal Stream Operations A stream pipeline does not execute until a terminal operation is invoked on it; that is,…
Finding the First or Any Element The findFirst() method can be used to find the first element that is available…
Collecting to a List The method Stream.toList() implements a terminal operation that can be used to collect or accumulate the…
Collecting to a Set The method toSet() creates a collector that uses a mutable container of type Set to perform…
Averaging Another common statistics to calculate is the average of values, defined as the sum of values divided by the…