Is jCaptcha thread safe?

I'm using JCaptcha in a project and needed a behavior that was not directly available. so I looked into the source code to see if I can extend it to obtain what I want and开发者_StackOverflow中文版 found that the store implementation I use (MapCaptchaStore) uses a HashMap as the store... with no synchronization.

I know JCaptcha does not work in a clustered environment, it is not my case, but how about multiple clients at the same time? Is the store implementation synchronized externally or should I roll my own and make sure it is properly synchronized?

TIA!

Judging by the reading source for MapCaptchaStore, this class is NOT thread-safe. I'm not 100% willing to stand behind this answer though, because synchronisation may be happening at a higher level (eg all accesses to a single instance of MapCaptchaStore may be synchronised on another object).

You could use another implementation of CaptchaStore. For example, EhcacheCaptchaStore

Basic hashmap implementation of the captcha store is not synchronized, that could lead to some weird behaviour. Other stores are thread safe, for a simple implementation use FastHashMapCaptchaStore.

I'm assuming it is because it has been designed to be integrated with web applications which will always have multiple clients. It's also a CAPTCHA framework so they must have tested with both human and computer clients.

However, I would still recommend testing whether it behaves correctly in a multithreaded environment.