How to Filter a Collection Using Streams in Java?

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Java 8 introduced the Stream API, which allows for functional-style operations on collections. One of the most common use cases is filtering a collection based on certain conditions. In this article, we’ll explore how to filter a collection using streams in Java, covering the basics, advanced techniques, and best practices.

What are Java Streams?

Java streams are a sequence of elements supporting parallel and functional-style operations. They’re designed to work with collections, allowing you to process data in a declarative way. Streams don’t store data; instead, they provide a pipeline for processing data.

To understand Java streams, let’s consider an analogy. Imagine you’re at a coffee shop, and you want to order a coffee. You don’t need to know how the coffee is made; you simply tell the barista what you want. In a similar way, when working with Java streams, you specify what you want to do with your data, and the Stream API takes care of the details.

Creating a Stream

To filter a collection using streams, you first need to create a stream from the collection. You can do this using the stream() method, which is available on most collection classes, such as List, Set, and Map.

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