Implement Fork/Join pattern

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Description

The Fork/Join pattern is a concurrency design approach that splits (“forks”) a large task into multiple smaller subtasks, processes these subtasks in parallel, and then recombines (“joins”) their results. In Java, this pattern is embodied by the ForkJoinPool and RecursiveTask / RecursiveAction classes within the java.util.concurrent package. It’s particularly useful for CPU-intensive, divide-and-conquer problems where parallel processing can significantly reduce completion time.

Key Elements

• Divide-and-Conquer: Recursively split tasks into smaller chunks until reaching a manageable size.
• Parallel Processing: Distribute subtasks across a pool of worker threads (usually a ForkJoinPool).
• Work Stealing: Idle threads “steal” tasks from busy threads’ queues to optimize utilization.
• RecursiveTask / RecursiveAction: Abstract classes for defining the task logic and splitting strategy (RecursiveTask returns a result, RecursiveAction does not).

References

1. Java Documentation for ForkJoinPool
2. Java Concurrency in Practice – Brian Goetz
3. Java Design Patterns – Contribution Guidelines

Acceptance Criteria

• Create a new module or package named fork-join (or similar).
• Demonstrate splitting a computationally intensive task into subtasks using RecursiveTask or RecursiveAction.
• Show how the results are joined together for a final outcome.
• Provide a README (or .md file) explaining the pattern with diagrams or code snippets.
• Include tests verifying parallel execution and correctness of results.
• Ensure all code meets the repository style, naming conventions, and passes CI checks.