Resolve IP Address of microservice instance in spring could [jhipster]

I am using Jhipster to create a simple microservices architectures, basically I have an Eureka registry running,to whom a bunch of microservices instances are registered.

Some microservices need to talk to other microservices or query some data, but each microservice has a dynamic IP address, is it possible to use the instanse name to resolve IP and do the request ?

This is already provided by the JHipster Eureka architecture.

• The microservices (Eureka clients) register with the registry (Eureka server).
• Then, each microservice that sets the eureka.client.fetch-registry property to true gets its Ribbon instance configured and can connect to other registered services using service name URL like http://<service name>/api/something using a RestTemplate or a FeignClient

You did not say what kind of authentication you chose, this doc is for UAA and it might help even for plain JWT: https://www.jhipster.tech/using-uaa/#inter-service-communication

You can use server side load balancing pattern. Netflix Zuul as API gateways offers you that kind of balancing (use Netflix Ribbon as load balancer).
In your case: create Zuul µservice (don't forget annotation@EnableZuulProxy) and register it in Eureka.

After these steps you'll be able to call your µservice instances registred in Eureka via Zuul µservice address without knowing their addresses on the client side.