By default, the services built on top of Light have HTTP 2.0 enabled automatically right of the light-codegen. The server also supports HTTP 1.1 connection if the client cannot negotiate HTTP 2.0 with the server.
There are a lot of benefits with HTTP 2.0, but JDK 8 and below don’t support it natively. Though there are some workarounds, none of them is a practical solution. Given the situation, we have built a client module based on Undertow core for HTTP 2.0 support.
Here are some links regarding HTTP 2.0 and HTTP 1.1
If you are sure that the service is built on light-4j and HTTP 2.0 is not disabled. Then you should use HTTP 2.0 from the consumer side to enjoy the fast speed and single connection multiplexing.
Other Java HTTP Client
Most Java HTTP Client doesn’t support HTTP 2.0, or you have to find a workaround to do that with bootclasspath jar file per version of JDK on Java 8. If you are using Java 11, then it has native support for HTTP 2.0; however, it is never been tested with the foundation framework.