Deep Dive: Java Stream class

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In the realm of functional programming, Stream has gained immense popularity, and Java 8 gave it to us. Even though it’s been with us for some years now, not everyone has mastered using it. Let’s take a deep dive into the Java Stream Class.

The Stream Class

Introduced in Java 8, Stream is a sequence of elements supporting sequential and parallel aggregate operations. It helps in achieving functionality like SQL statements. However, contrary to popular belief, it’s not a data structure but more of a view onto a data structure.

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Stream<String> stream = Stream.of("Java", "Python", "C++", "JavaScript");

Note

Stream operations exploit the capability of multi-core processors, where each task is assigned to a separate core of the processor.

Stream Class Methods

Below are examples of some methods available in the Stream class:

  1. forEach()

forEach() method helps in iterating over each element of the stream.

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stream.forEach(elem -> System.out.println(elem));
  1. map()

map() method is used to convert - or map - a Stream of size ‘n’ to another Stream of size ‘n’.

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stream.map(String::toUpperCase).forEach(System.out::println);
  1. filter()

filter() method is used for filtering data based on certain conditions.

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stream.filter(s -> s.startsWith("J")).forEach(System.out::println);
  1. sorted()

sorted() method is used to sort a Stream.

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stream.sorted().forEach(System.out::println);

Conclusion

The power of Stream lies in its ability to exploit the declarative programming approach, making the best use of multi-core architecture. It might seem a little complex initially, but with practice, you will realize its benefits. Keep practicing and improving, Happy Coding!

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Stream<String> stream = Stream.of("Java", "is", "Love");
stream.forEach(System.out::println);

Remember, stream() away until you master the flow.