Efficient API Responses in Java Spring Boot: Removing Duplicates

When developing APIs, ensuring clean and duplicate-free data is essential for efficiency and performance. Recently, I encountered a scenario where my API returned duplicate analysts assigned to a worksheet. To solve this, I leveraged Java's Set collection.

The Challenge

While fetching assigned analysts, duplicate records sometimes appeared in the response. This not only cluttered the data but also impacted processing efficiency. A traditional List wasn't ideal, as it required manual checks for duplicates.

The Solution: Using a Set

To eliminate duplicate analysts, I opted for a Set instead of a List. Since a Set only stores unique elements, any repeated analyst entries were automatically filtered out. This significantly simplified the code and improved API performance.

Example Implementation

Here's a simple approach to removing duplicates from a list using a Set in Java:

public List removeDuplicates(List names) {
    return new ArrayList<>(new HashSet<>(names));
}

This method converts the list into a HashSet, eliminating duplicates, and then back into a list for the final output.

Alternatively, using Java Streams:

public List removeDuplicatesWithStream(List names) {
    return names.stream().distinct().collect(Collectors.toList());
}

This approach leverages the distinct() method to filter out duplicates in a more functional style.

Why Use a Set?

• Automatic Deduplication – No need for additional checks.
• Better Performance – More efficient than filtering a List manually.
• Simpler Code – Reduces complexity and potential errors.

Lessons Learned

Initially, I considered checking for duplicates manually, but using a Set turned out to be a cleaner and more efficient approach. This experience reinforced the importance of choosing the right data structures for API optimization.

Final Thoughts

Handling duplicate data efficiently improves both performance and user experience. By implementing a Set, I ensured a clean and accurate API response with minimal effort. If you encounter a similar issue, consider using a Set—it might just be the perfect solution!

By implementing these techniques, you can significantly reduce your API response sizes and improve the performance of your Spring Boot applications, especially when dealing with complex object graphs and relationships.