Remove Duplicates from Java ArrayLists: 2 Efficient Solutions

Effortless Duplicate Removal: A Java ArrayList Refresher

When working with Java ArrayLists, duplicate elements can be a major hassle. But fear not, dear developer! We’ve got two sleek solutions to remove duplicates and keep your code tidy.

The Set Solution: A Simple yet Effective Approach

Imagine having an ArrayList named numbers containing duplicate elements. To remove these duplicates, we can utilize the power of Java Sets. Here’s how:

1. Add all elements from the ArrayList to a Set: This automatically removes duplicates, thanks to the Set’s inherent properties.
2. Clear the ArrayList using the clear() method: Start with a clean slate!
3. Add all elements from the Set back to the ArrayList: Voilà! Your ArrayList is now duplicate-free.

But why did we choose LinkedHashSet specifically? It’s because this implementation maintains the insertion order while removing duplicates. Want to learn more about LinkedHashSet? We’ve got you covered!

The Stream Solution: A Modern Approach

In our second example, we’ll harness the power of Java Streams to remove duplicates from the numbers ArrayList. Here’s the step-by-step process:

1. Create a Stream from the ArrayList using numbers.stream(): This sets the stage for our duplicate-removal magic.
2. Use stream.distinct() to remove duplicate elements: This method does the heavy lifting for us, ensuring only unique elements remain.
3. Collect the results into a List using stream.collect(Collectors.toList()): Finally, we convert the Stream back into a List, which we can then typecast into an ArrayList.

With these two solutions, you’ll be well-equipped to tackle duplicate elements in your Java ArrayLists. So, which approach will you choose?