There is a dependency jar containing tons of service classes mostly used to retrieve data from database, and this jar is used among several different micro services in one cluster.

There is a big problem in such architecture: once a new method is added to any of the service class in the dependency jar, it is next to impossible to change the method signature, since the method might be used already by several micro services. This causes big maintenance cost on those service classes

Question: how to reduce the maintenance cost on the shared service jar? is there better alternative to share those service dependency jar among the microservices?