Your Guide to Java Streams [Tutorials and Articles]

In this edition of "Best of DZone," we've compiled our best tutorials and articles on one of the most popular APIs in Java, Streams. Whether you're a beginner just looking to bring in some elements of functional programming into a Java application, or a Streams vet, we've got your back!

Before we begin, we'd like need to thank those who were a part of this article. DZone has and continues to be a community powered by contributors like you who are eager and passionate to share what they know with the rest of the world. 

Let's get started!

Overview

• A Guide to Streams: In-Depth Tutorial With Examples by Eugen Paraschiv — Java 8 and streams: A match made in heaven, but it can be a little overwhelming. In this post, we take an in-depth look at this combination with some examples.

• Dipping Into Java 8 Streams by Dan Newton — With a working knowledge of lambda expressions and method references, you can see how streams enable you to work with Collections while efficiently adding logic.

• Java Streams Overview, Part 1 and Part 2 by Zoltan Raffai — Get started working with Streams and learn everything you need to get started with basic classes, reading and writing operations, and working with errors. 

• A Java 8 Streams Cookbook by Martin Farrell — If you're looking for a quick breakdown of Streams, look no further. This cookbook covers Streams' chief advantages, its operations, and a comprehensive example.

Processing Collections

• Process Collections Easily With Stream in Java 8 by Leona Zhang — Learn how you can process collections easily with Stream in Java 8.

• How to Compare List Objects in Java 7 vs. Java 8 by Arpan Das — In this blast from the not-too-distant past, we compare how Java 8's Stream API changed how you can compare List objects.

• Mastering Java 8 Streams Part 1 and Part 2 by Marco Behler — Want to get your feet wet with Java streams? This introductory video will get you creating streams and performing simple tasks on them.

• Convert a List to a Comma-Separated String in Java 8 by Mario Pio Gioiosa — This quick tutorial shows you how to use streams in Java to convert the contents of a list to a comma-separated string in Java 8.

Working With Files

• Split a File as a Stream by Peter Verhas — Curious about when you would actually use the splitAsStream method? Here's a use case of splitting a file into chunks that can be processed as streams.

• Java 8 Stream and Lambda Expressions – Parsing File Example by Eyal Golan — See a common use case for Streams and Lambda Expressions in this article.

Parallel  Streams

• Think Twice Before Using Java 8 Parallel Streams by Lukas Krecan — Parallelization was the main driving force behind lambdas, stream API, and others. Let's take a look at an example of stream API.

• Should I Parallelize Java 8 Streams? by Santhosh Krishnan — What do we need to consider before parallelizing Java streams?

Streams and Collectors 

• Using Java Streams and Collectors by Jay Sridhar — This short guide covers how to use Java 8 Streams and Collectors to slice and dice lists, including computing sums, averages, and partitioning.

• How to Use Java Stream Collectors by Yogen Rai — Want to learn more about using Java Stream collectors? Check out this post on collectors and how to use them.

• How to Transform Elements In a Stream Using a Collector by Hubert Klein Ikkink — Learn more about how to transform elements in a Stream using Java Collectors.

• The Ultimate Guide to the Java Stream API groupingBy() Collector by Grzegorz Piwowarek — Still a bit puzzled by what the groupingBy() collector can do in the Java Stream API? Check out this guide on using the groupingBy() collector to its fullest potential.

Stream Bugs

• Java Stream API Was Broken Before JDK 10 by Grzegorz Piwowarek — Stream API bugs can affect anyone still residing on JDK 8 and JDK 9. Click here to learn more.

Lambda Streams

• Java Lambda Streams and Groovy Closures Comparisons by Alex Staveley — Want to learn more about the difference between in lambda streams in both Java and Groovy? Check out this post to learn more about the differences between them.

Advanced Topics 

• Are Java 8 Streams Truly Lazy? Not Completely! by Lukas Eder — Is it always the case that streams in Java 8 are evaluated lazily? Check out this article and find a possibly surprising result.

• Overview of Java Stream API Extensions by Piotr Mińkowski — Check out the top Java Stream API extensions offered by popular Java libraries.

• Java Stream: Is a Count Always a Count? Part 1 and Part 2 by Per-Åke Minborg — Learn more about counts in Java streams.

• How to Reuse Java Streams by Miguel Gamboa — Need to use your streams over and over again? Let's cover three different approaches, their benefits, and their pitfalls when recycling Java streams.

• Become a Master of Java Streams, Part 1: Creating Streams, Part 2: Intermediate Operations, Part 3: Terminal Operations, and Part 4: Database Streams, Part 5: Turn Joined Database Tables Into a Stream, and Part 6: Creating a New Database Application Using Streams by Per-Åke Minborg and Julia Gustafsson — Want to become a Java Streams Master?

• Exception Handling in Java Streams by Brian Vermeer — When you want to use a method that throws a checkedException, you have to do something extra if you want to call it in a lambda.

• Peeking Inside Java Streams With Stream.peek by Dustin Marx — How to use the Stream.peek(Consumer) method in Java to help visualize stream operations.

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Further Reading

• The Best of Java Collections [Tutorials].
• The Complete Apache Spark Collection [Tutorials and Articles].