How do open source libraries like Apache Commons fit into the microservices architecture?

Question

I'm reading about microservices, and one point I come across repeatedly, is, in order to achieve full indepencency, it's a bad idea to share libraries among microservices. Examples are here and here.

But how do open source libraries fit into this image? Can I use Apache Commons or Guava? If I'm using Apache Commons Lang in multiple services, would that mean I create dependencies, opposing the aim of a microservices architecture to create independent services?

• Vincent Savard: Sharing dependency is bad if that means that when you change that dependency, you have to update multiple services. If you use a general purpose library, it doesn't matter if one microservice uses version 1 and another uses version 2.

Answer 1

It's about libraries created by you to share common functionality when you're trying to avoid rewriting the same code in your multiple microservices. It creates a situation where you have a (loose) dependency between the microservices through the shared library.

This can create problems such as needing to modify the shared library to satisfy a requirement for one microservice, whereas the other microservice will not expect this new functionality and may break.

It has nothing to do with using third party libraries in your microservices.