What was the last approach or method you used to improve the performance or efficiency of a project?

To improve the performance of a Java project, I often apply the following approaches:

• Using efficient collections from java.util (for example, ArrayList instead of LinkedList for faster index access).
• Optimizing algorithms, reducing the complexity of operations.
• Caching results of expensive computations.
• Profiling the application with tools (such as VisualVM) to identify bottlenecks.

Example: to speed up element search in a large dataset, I replaced iteration with the use of HashSet, which reduced the search time from O(n) to O(1):

Set<String> set = new HashSet<>(list);
if (set.contains("target")) {
    // action
}

This approach significantly increased data processing efficiency.