Is there such an Open Source (preferably Java, but not required) engine?

Question

Java

Good afternoon,
I'm planning to open something like an online exchange, so I'm wondering if there are any ready-made open source developments. I know Java best of all, so it would be preferable to use it, because. in any case, a lot of work will have to be done, but the language is not critical.
I looked at ready-made engines for online stores, but this is not the same, because I want to give the client the opportunity to manage their own goods.

PS Since the purpose of my future project is “Let's hit corruption with information technologies”, then people are invited who are ready to devote their evenings to working on the project.

Answer 1

>I want to provide the client with the opportunity to manage their own goods
In general, all popular CMS online stores have the ability to manage goods.
The exchange and the online store are different groups of software.