Converting Iterable to Stream in Java 8 JDK

Problem:

How can I manipulate an Iterable using the Java 8 Stream API without converting it to a List?

Solution:

tl;dr: Use StreamSupport.stream(iterable.spliterator(), false) to create a stream from the iterable.

Detailed Explanation:

Iterable provides a spliterator() method that returns a Spliterator, which can be used to create a stream using StreamSupport.stream. Here's the code snippet:

StreamSupport.stream(iterable.spliterator(), false)
    .filter(...)
    .moreStreamOps(...);

This approach avoids unnecessary conversion to a List, which can improve performance and memory consumption. StreamSupport.stream takes two arguments:

• iterable.spliterator(): The Spliterator obtained from the Iterable.
• false: Specifies that the iterable does not have a known size.

The resulting stream can then be manipulated using Stream API operations like filter, map, etc.

Benefits:

Using StreamSupport.stream provides the following benefits:

• Convenience: Simpler and less error-prone than manually handling spliterators.
• Efficiency: Gets a better spliterator and stream performance, especially when the Iterable is already a collection.
• Memory Savings: Avoids unnecessary conversion to a List, reducing memory overhead.