Welcome to Bank-Transaction-System Discussions!

[vaidikaggarwal]

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[johnmacha]

Hello am John a backed dev. I'm currently working on Java and I realized that data structures such as HashMaps are really essential when dealing with Bank transactions especially by making each account individual. I think that would be really vital when implementing encapsulation.

[vaidikaggarwal]

Hey John, really appreciate you bringing this up - you're absolutely on the right track.

Using HashMaps in banking systems is actually a very practical choice, especially when you map something like accountId -> AccountObject. It allows constant-time access, which becomes critical when you're dealing with frequent transactions and real-time operations.

I also like that you connected this with encapsulation. Ideally, each Account object should manage its own state (balance, transaction history, etc.), while the HashMap acts as a registry or lookup layer. This separation keeps things clean and scalable.

That said, I think it opens up a few interesting points worth discussing further:

How would you handle concurrency? (e.g., multiple transactions on the same account - would you use synchronization, locks, or something like ConcurrentHashMap?)
Would you keep transaction logic inside the Account class or introduce a separate service layer?
How would you design it to persist data beyond memory (since HashMap is in-memory)?

Curious to hear your thoughts on these - especially how you'd approach thread safety in a real-world banking scenario.

[johnmacha]

Hey too, thank you for the heads up. That's quite informative I would say for concurrency I would go for ConcurrentHashMap and since am using a framework which is Spring Boot in my case I would keep the transaction logic inside the service layer as a separate class and for data persistence am not quite sure how I should answer but I would say integrating a database such as MySQL with the application.properties file and Maven