3 ms·

Ask HN: How to learn concurrency?

Race condition, producer consumer, and cool stuffs like that? I do java

scorpioxy 11mo ago
That's a huge topic but I would say implement a hobby project and learn by doing. Pick something you're interested in and start writing code to exercise the theoretical concepts. A small piece of advice is to make sure you're motivated before diving in. Debugging a race condition, just as an example, can be quite involved and consume a lot of your time and energy to even reproduce.
- ykonstant 11mo ago
  But what is a good hobby project with a strong focus on concurrency that will not swamp a beginner to this topic?
  - peauc 11mo ago
    I started by writing a user interface that handled they keyboard events in a thread and communicated to the main thread using a message queue. IMO that's a good easy first step :)
  - nrhrjrjrjtntbt 11mo ago
    Try making a trading order book system. Maybe in Go where they have made concurrency easier than other languages.
sigmaprimus 11mo ago
Brilliant.org?
Rendello 11mo ago
Everything I know is from desperately trying to parallelize my TIS-100 solutions.
serendipty01 11mo ago
https://deadlockempire.github.io/ https://deadlockempire.github.io/ https://thecomputersciencebook.com/book/concurrent-programming/ https://thecomputersciencebook.com/book/concurrent-programmi...
pestatije 11mo ago
https://docs.oracle.com/en/java/javase/25/core/concurrency.html https://docs.oracle.com/en/java/javase/25/core/concurrency.h...
Pooge 11mo ago
Java Concurrency in Practice[1] has always been recommended by my colleagues. I'm about halfway through it and I think it makes the concepts pretty clear. Even if you move away from Java one day, I think the investment is not lost at all. Then you could ask your favorite LLM to create concurrency exercises once in a while to practice. [1]: ISBN 978-0321349606
propablythrown 11mo ago
[flagged]
- netsharc 11mo ago
  Or an LLM... Curious how this stackoverflow-first-grader question isn't flagged to death.
  - propablythrown 11mo ago
    People in the comments wish to provide assistance and share their experience, clearly missing the fact that the person asking didn't even bother to do a simple search first.
liampulles 11mo ago
Something I've built for myself (in Go) that has been extremely useful is a lib to read a CSV that delegates to n concurrent workers. Maybe that is a good side project.
throwaway81523 11mo ago
Read a book about OS's I guess. This should be good, an update of an earlier good book: https://www.os-book.com/OS10/ https://www.os-book.com/OS10/ There was a Java-specific edition: https://www.os-book.com/OS8/os8j/index.html https://www.os-book.com/OS8/os8j/index.html
rramadass 11mo ago
1) Foundations of Multithreaded, Parallel, and Distributed Programming by Gregory Andrews - https://www2.cs.arizona.edu/~greg/mpdbook/ https://www2.cs.arizona.edu/~greg/mpdbook/ This will give you a solid foundation in all aspects of concurrency. 2) The Art of Multiprocessor Programming by Herlihy, Shavit et al. - https://shop.elsevier.com/books/the-art-of-multiprocessor-programming/herlihy/978-0-12-415950-1 https://shop.elsevier.com/books/the-art-of-multiprocessor-pr... The classic must-study book. Both the above are not language specific but do have examples in Java.
- Cwizard 11mo ago
  I read the “The Art of Multiprocessor Programming” and I don’t recommend it. It is very theoretical. There is no mention of practical performance considerations on real hardware. Large parts of the theory focus on lock-free and wait-free data structures. Which, while interesting, are not necessary for beginners.
ashed96 11mo ago
Once you've gone through the learning resources others shared, LeetCode has a dedicated concurrency section for hands-on practice: https://leetcode.com/problemset/concurrency/ https://leetcode.com/problemset/concurrency/ (I actually authored a few of those problems - they cover the classic scenarios like producer-consumer, dining philosophers, etc.)
another_twist 11mo ago
Docs of java.util.concurrent would be my suggestion. And go straight into the wild and try to build a system that solves the billion rows challenge. You might want to truncate the input and start with a million row challenge first. The cool stuff in concurrency is not having to deal with it imoand recognizing when its not essential. Also I hope you mean concurrency not parallelism. The second one is a bit more manageable.
notorious_pgb 11mo ago
Do you know, deep down, what a thread is? What it actually is? If not, I suggest reading this blog post: https://prettygoodblog.com/p/what-threads-are-part-2 https://prettygoodblog.com/p/what-threads-are-part-2 (disclaimer: I wrote this)
luhego 11mo ago
If you don’t mind learning another language. I have found Learn Concurrent Programming with Go by James Cutajar to be a very practical book. It includes memory sharing and message passing approaches with plenty of examples. It also explains concepts like mutual exclusion, deadlock-free and starvation-free properties and others. For Java, you can try The Art of Multiprocessor Programming Second Edition. It includes examples in Java but it is more theoretical and it includes a lot of proofs, specially the first half. The second half is more approachable.
dvcoolarun 11mo ago
https://github.com/dabeaz/concurrencylive https://github.com/dabeaz/concurrencylive

Race condition, producer consumer, and cool stuffs like that? I do java

That's a huge topic but I would say implement a hobby project and learn by doing. Pick something you're interested in and start writing code to exercise the theoretical concepts. A small piece of advice is to make sure you're motivated before diving in. Debugging a race condition, just as an example, can be quite involved and consume a lot of your time and energy to even reproduce.

ykonstant 11mo ago
But what is a good hobby project with a strong focus on concurrency that will not swamp a beginner to this topic?
- peauc 11mo ago
  I started by writing a user interface that handled they keyboard events in a thread and communicated to the main thread using a message queue. IMO that's a good easy first step :)
- nrhrjrjrjtntbt 11mo ago
  Try making a trading order book system. Maybe in Go where they have made concurrency easier than other languages.

sigmaprimus 11mo ago

Brilliant.org?

Rendello 11mo ago

Everything I know is from desperately trying to parallelize my TIS-100 solutions.

serendipty01 11mo ago

https://deadlockempire.github.io/ https://deadlockempire.github.io/ https://thecomputersciencebook.com/book/concurrent-programming/ https://thecomputersciencebook.com/book/concurrent-programmi...

pestatije 11mo ago

https://docs.oracle.com/en/java/javase/25/core/concurrency.html https://docs.oracle.com/en/java/javase/25/core/concurrency.h...

Pooge 11mo ago

Java Concurrency in Practice[1] has always been recommended by my colleagues. I'm about halfway through it and I think it makes the concepts pretty clear. Even if you move away from Java one day, I think the investment is not lost at all. Then you could ask your favorite LLM to create concurrency exercises once in a while to practice. [1]: ISBN 978-0321349606

propablythrown 11mo ago

[flagged]

netsharc 11mo ago
Or an LLM... Curious how this stackoverflow-first-grader question isn't flagged to death.
- propablythrown 11mo ago
  People in the comments wish to provide assistance and share their experience, clearly missing the fact that the person asking didn't even bother to do a simple search first.

liampulles 11mo ago

Something I've built for myself (in Go) that has been extremely useful is a lib to read a CSV that delegates to n concurrent workers. Maybe that is a good side project.

throwaway81523 11mo ago

Read a book about OS's I guess. This should be good, an update of an earlier good book: https://www.os-book.com/OS10/ https://www.os-book.com/OS10/ There was a Java-specific edition: https://www.os-book.com/OS8/os8j/index.html https://www.os-book.com/OS8/os8j/index.html

rramadass 11mo ago

1) Foundations of Multithreaded, Parallel, and Distributed Programming by Gregory Andrews - https://www2.cs.arizona.edu/~greg/mpdbook/ https://www2.cs.arizona.edu/~greg/mpdbook/ This will give you a solid foundation in all aspects of concurrency. 2) The Art of Multiprocessor Programming by Herlihy, Shavit et al. - https://shop.elsevier.com/books/the-art-of-multiprocessor-programming/herlihy/978-0-12-415950-1 https://shop.elsevier.com/books/the-art-of-multiprocessor-pr... The classic must-study book. Both the above are not language specific but do have examples in Java.

Cwizard 11mo ago
I read the “The Art of Multiprocessor Programming” and I don’t recommend it. It is very theoretical. There is no mention of practical performance considerations on real hardware. Large parts of the theory focus on lock-free and wait-free data structures. Which, while interesting, are not necessary for beginners.

ashed96 11mo ago

Once you've gone through the learning resources others shared, LeetCode has a dedicated concurrency section for hands-on practice: https://leetcode.com/problemset/concurrency/ https://leetcode.com/problemset/concurrency/ (I actually authored a few of those problems - they cover the classic scenarios like producer-consumer, dining philosophers, etc.)

another_twist 11mo ago

Docs of java.util.concurrent would be my suggestion. And go straight into the wild and try to build a system that solves the billion rows challenge. You might want to truncate the input and start with a million row challenge first. The cool stuff in concurrency is not having to deal with it imoand recognizing when its not essential. Also I hope you mean concurrency not parallelism. The second one is a bit more manageable.

notorious_pgb 11mo ago

Do you know, deep down, what a thread is? What it actually is? If not, I suggest reading this blog post: https://prettygoodblog.com/p/what-threads-are-part-2 https://prettygoodblog.com/p/what-threads-are-part-2 (disclaimer: I wrote this)

luhego 11mo ago

If you don’t mind learning another language. I have found Learn Concurrent Programming with Go by James Cutajar to be a very practical book. It includes memory sharing and message passing approaches with plenty of examples. It also explains concepts like mutual exclusion, deadlock-free and starvation-free properties and others. For Java, you can try The Art of Multiprocessor Programming Second Edition. It includes examples in Java but it is more theoretical and it includes a lot of proofs, specially the first half. The second half is more approachable.

dvcoolarun 11mo ago

https://github.com/dabeaz/concurrencylive https://github.com/dabeaz/concurrencylive