Any webservice which supports GraphQL is consumable through a Java implementation? Because "it provides an alternative to REST..."?
See Question&Answers more detail:osAny webservice which supports GraphQL is consumable through a Java implementation? Because "it provides an alternative to REST..."?
See Question&Answers more detail:osGraphql-java (that you linked to) is an implementation of the GraphQL specification. As such, it is used to create GraphQL servers. A client doesn't need anything special to consume a service, just like it doesn't need anything special to consume a REST service - only to be be able to speak HTTP. You can use any generic HTTP client you like.
Still, you have some more convenient options for creating clients (but both somewhat lacking):