Java Stream intermediate operations ¶

In Java 8, Stream intermediate operations are operations that transform a Stream into another Stream.^[java8.md] They form a pipeline through which data flows, allowing for lazy and chained processing of data.

Creating a Stream¶

Before intermediate operations can be applied, a Stream must be created. Common sources include arrays or collections^[java8.md]:

From Arrays: Arrays.stream(new int[] {1, 2, 3})^[java8.md]
From Collections: Arrays.asList(1, 2, 3).stream()^[java8.md]
Static Methods: Stream.of(1, 2, 3)^[java8.md]
Concatenation: Stream.concat(s1, s2)^[java8.md]

Core Intermediate Operations¶

Filtering¶

filter(Predicate): Used to exclude elements from the stream based on a condition^[java8.md].
```
nums.stream().filter(x -> x > 2).forEach(System.out::println);
```
distinct(): Returns a stream consisting of distinct (unique) elements, removing duplicates^[java8.md].
limit(long n): Retains only the first n elements of the stream^[java8.md].

Mapping¶

map(Function): Transforms each element by applying a function to it, creating a new stream of those results^[java8.md].
```
words.stream().map(String::toUpperCase).forEach(System.out::println);
```
flatMap(Function): Transforms each element into a stream, and then flattens the resulting streams into a single stream^[java8.md]. This is useful for handling collections of collections or one-to-many transformations.

Sorting¶

sorted(): Sorts the elements of the stream according to their natural order^[java8.md].
sorted(Comparator): Sorts the elements using a specific Comparator to define the sorting rules^[java8.md].

[[Java Stream]]
[[Java 8]]
[[Functional Interfaces]]
[[Lambda expressions]]

Sources¶

^[java8.md]

Java Stream intermediate operations¶