Stream.distinct() in Java

The distinct() method in Java is used to remove duplicate elements from a stream. It returns a new stream containing only unique elements based on the equals() and hashCode() methods.

• It is an intermediate operation, meaning it returns a stream and does not produce a final result by itself.
• For ordered streams, the order of elements is preserved.
• For unordered streams, the order of distinct elements is not guaranteed.
• It is a stateful operation because it keeps track of previously seen elements.

Example:

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Explanation:

• stream() converts the list into a stream.
• distinct() removes duplicate elements using equals() and hashCode().
• forEach() prints each unique element.

Syntax

Stream<T> distinct()

Example 1: This program demonstrates how to use the Stream.distinct() method in Java to remove duplicate elements from a stream.

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Explanation:

• distinct() filters out duplicate strings using equals() and hashCode().
• forEach(System.out::println) prints each unique element from the stream.

Example 2: This program counts the number of distinct elements in a list using the Stream.distinct() method

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Explanation: count() returns the total number of unique elements in the stream.

Related Topics:

• Java Stream API
• Stream.filter()
• Stream.map()