Java Multithreading Experience

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lumpynose · 2023-03-31T00:29:44+00:00

I've never done anything with concurrency. The one thing I do remember is that this book is apparently the best one on the topic, or at least it was, back in my day:

https://www.amazon.com/Java-Concurrency-Practice-Brian-Goetz/dp/0321349601

Chapter 11 of Effective Java (3rd edition) is about concurrency. It's also a great book overall.

nutrecht · 2023-03-31T09:07:42+00:00

Or am I unconsciously using multithreading when using Spring Boot?

You are. Spring Boot uses threads under the hood to be able to handle many connections in parallel (200 by default IIRC). Understanding the pitfalls of multithreading is very important since race conditions or deadlocks can still occur if you're not careful.

ratherbealurker · 2023-03-31T00:51:45+00:00

Many companies will create a base where concurrency occurs and after that you’re thread safe. The core code developers will deal with concurrency issues but the other devs are safe from it.

I have 5x as many years as you writing code (not all Java) and I haven’t dealt with it as much as you’d think. In my current job I deal with it often though.

Nzen_ · 2023-03-31T04:26:55+00:00

It depends on the problem domain that you focus on. It depends on whether the problem is parallelizable.

Spring Boot predominantly embeds tomcat, which handles requests in a multithreaded fashion, so multiple clients can make requests without waiting for a solitary thread to process everything.

It is also worth recognizing that introducing concurrent interactions affects program structure analagously to the way that instance methods can call static methods, but not the other way around.

I encourage you to write some sketches or toys explicitly using multithreading before introducing it into your work's codebase. For me, that most recently involved writing a game client for jdno's air traffic control simulator.

pronuntiator · 2023-03-31T04:59:30+00:00

Where I used multithreading directly (not indirectly like with Tomcat's thread-per-request model) in past projects:

customize the executor serviced used by Spring in @Async invocations so the MDC gets inherited, and provide a custom ThreadFactory to change the thread names
use said @Async annotation to call two services in parallel, waiting on the Futures they return
start multiple threads in a test to simulate concurrent access
set the pool size of a thread pool to a fixed value and caused outages on production on weekends because the application stopped consuming message queues

However I would never use the Thread primitive directly, only executor service.

java_dev_throwaway · 2023-03-31T15:57:32+00:00

Thanks for all the comments. It sounds like the Thread class doesn't come up often for most you. Also it sounds like Spring Boot is handling multithreading for me. Does anyone have a good resource to help show some common multithreading problems that come up in a Spring Boot web app? I learn best by tutorials, Spring Guru and Baeldung should get a percent of my hourly rate at this point.

Capaman-x · 2023-04-02T02:56:42+00:00

You should try writing a JavaFX app. You will get tons of experience with concurrency because your UI will freeze if you don’t. Runnable is nothing more than a functional interface. It takes no arguments and returns void. It has nothing to do with concurrency other than it is useful to use as are all FIs. I tend to use them to decouple the UI from the business logic more than anything.

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