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 theForkJoinPool andRecursiveTask /RecursiveAction classes within thejava.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 aForkJoinPool).
• 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 forForkJoinPool
2. Java Concurrency in Practice – Brian Goetz
3. Java Design Patterns – Contribution Guidelines

Acceptance Criteria

• Create a new module or package namedfork-join (or similar).
• Demonstrate splitting a computationally intensive task into subtasks usingRecursiveTask orRecursiveAction.
• 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.