Refactored BallThread to replace busy-waiting with wait/notify

[PRASHANTS19]

Pull Request: Fix busy-waiting loop in BallThread (Twin pattern)

What does this PR do?

This pull request addresses issue #2977, which highlights the use of inefficient busy-waiting loops in some classes.
I have refactored the BallThread class in the Twin pattern to replace busy-waiting with a proper synchronization mechanism using wait() and notify().

Why is this change important?

• ✅ Reduces CPU usage by eliminating unnecessary spinning
• ✅ Improves responsiveness and efficiency of the thread
• ✅ Follows best practices in concurrent programming
• ✅ Makes code cleaner and easier to understand

Changes made

• Replaced the while (isRunning) { if (isSuspended) ... } pattern with synchronized wait() and notify()
• Introduced a lock object for thread coordination
• Updated suspendMe(), resumeMe(), and stopMe() methods accordingly
• Maintained existing functionality and ensured thread safety
• Verified correctness using existing unit tests in BallThreadTest

Testing

• ✔️ Verified via BallThreadTest.java using mvn test
• ✔️ Confirmed the tests pass and cover both suspension and resumption scenarios

Checklist

• My code follows the design and contribution guidelines
• I ran mvn spotless:apply to fix formatting
• I verified this change with existing unit tests
• I’ve linked this PR to the issue using Fixes #2977
• This is my first PR to this repository 🎉

Related Issue

Fixes #2977

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Let me know if you'd like help reviewing the PR once it's live — happy to support!

[github-actions]

PR Summary

This PR refactors the BallThread class in the Twin pattern to replace busy-waiting with a wait/notify mechanism, improving efficiency and responsiveness. It introduces a lock object for thread coordination and updates related methods (suspendMe, resumeMe, stopMe). The changes maintain existing functionality and thread safety, verified by unit tests.

Changes

File	Summary
twin/README.md	Updated README.md to reflect the changes made to BallThread. The documentation now includes a more detailed explanation of the new synchronization mechanism using wait() and notify().
twin/src/main/java/com/iluwatar/twin/BallThread.java	Refactored BallThread to use wait() and notify() for thread synchronization instead of busy-waiting. Added a lock object and updated suspendMe, resumeMe, and stopMe methods accordingly. Improved logging for better debugging.
twin/src/test/java/com/iluwatar/twin/BallThreadTest.java	Updated unit tests to verify the correctness of the changes made to BallThread. The tests now cover both suspension and resumption scenarios using the new synchronization mechanism.

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[github-actions]

✅ LGTM!

Review Summary

Commits Considered (1)

• db217fd: Refactored BallThread to replace busy-waiting with wait/notify

Files Processed (3)

• twin/README.md (1 hunk)
• twin/src/main/java/com/iluwatar/twin/BallThread.java (2 hunks)
• twin/src/test/java/com/iluwatar/twin/BallThreadTest.java (3 hunks)

Actionable Comments (0)

Skipped Comments (1)

• twin/src/main/java/com/iluwatar/twin/BallThread.java [102-107]

  enhancement: "Add clarifying comment about interrupt handling."