Consider providing a GraphQL Java client

[jvissers]

Environment Details

• Helidon Version: 4.0.7
• Helidon MP
• JDK version: Java HotSpot(TM) 64-Bit Server VM (build 21.0.2+13-LTS-58, mixed mode, sharing)
• OS: Ubuntu 23.10

---

Problem Description

In one of the components that we are using has certain functionality not exposed through the documented REST API so we have to instead use the GraphQL endpoint that is exposed. Using that GraphQL endpoint, and a GraphQL query we are able to get the information that we need. However, as there is no official Java GraphQL client available, we had to find a way to make this work.

In this particular case, we were able to leverage the MP REST Client, to POST a GraphQL JSon payload and deal with the JSon result. However, this is not very convenient.

I'm raising this issue as per request by @arjav-desai in order for the Helidon team to consider adding a genuine GraphQL client. This probably would look very similar to the concept of a MP REST Client, somewhat similar to SmallRye GraphQL Client