I've generated the Apollo classes successfully and can see them in the build directory, however they're not available on the classpath. Strangely the Enum that is generated is available but the classes themselves aren't.
Running the sample project provided on Apollo's Github does work but I cant see the difference between the configurations.
Right now, you have
src/main/graphql/ containing GraphQL documents. That means that your Java classes will be generated with no Java package, which probably is not what you want.
Instead, create a package tree under
src/main/graphql/apollotest/mq/apollotest/api/). Move the GraphQL documents and
schema.json there. Clean the project, and you should find that your Apollo-generated classes are available to you in whatever Java package you chose (e.g.,
apollotest.mq.apollotest.api in the above example).