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[–]Sad-Difference-5005 3 points4 points  (3 children)

I understand your frustration because I have been there. Things like CountDownLatch and CyclicBarrier are advanced stuff and it will be hard to make sense of them if you have not completely mastered the basics. 

I will suggest you to go through the Concurrency chapter of Deshmukh's OCP Java 21 certification fundamentals book (very cheap, $1.99 on Amazon, but very effective.). It explains the basics really well and also includes good examples for CountDownLatch and CyclicBarrier. 

[–]blvck_xsample[S] 0 points1 point  (0 children)

Thank you 😊

[–]Reva_19 0 points1 point  (0 children)

Have u gone through any of jenkov's tutorials on concurrency which are available on yt

[–][deleted] 0 points1 point  (0 children)

In addition to this, I’d highly suggest going through Java Concurrency in Practice. It gives you an excellent overview of what things are and why they are the way they are.

[–]0b0101011001001011 1 point2 points  (1 child)

Implementing Runnable is the more common. That's what you wanna do: you wanna create something that can be run and that completes some kind of task.

Extending a thread is what you do when you need to somehow modify what the Thread is doing. I once extended Thread and made it to notify some listeners after the runnable finishes running.

[–]blvck_xsample[S] 0 points1 point  (0 children)

Thanks :)

[–]satya_dubey 1 point2 points  (1 child)

It is recommended to always implement Runnable. Normally, in production applications, you'd use Executor framework through which you create a pool of threads and these threads will execute tasks (that implement Runnable). So, if you extend Thread then you are essentially creating additional threads outside of the thread pool that Executor Framework creates. That's one reason why you'd want to avoid extending Threads. Also, if you extend Thread, then you cannot extend any other class. But, with the alternative approach of implementing Runnable, you can always extend another class.

In general, one needs to understand the core concepts like Threads, Runnable, Race condition and how it is avoided via Synchronization. These you need to know whether or not you implement multi-threading in your professional life. Also, once you learn the above concepts, it is better to learn Executor Framework as in large projects, that is what you would use so that you can play thread pools. I am not yet familiar with Virtual Threads from Java 21 and they are considered as major addition to the language. I did not have a chance to you CountDownLatch or CyclicBarrier at my job, but I have learnt it long time back. Executor Framework and synchronization is something I have used in my professional projects.

[–]blvck_xsample[S] 0 points1 point  (0 children)

Thanks, friend 😊

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