lang/java/compiler/src/test/idl/input/bar.avpr

{"protocol": "org.foo.Bar",
 "types": [{"name":  "AorB", "type": "enum", "symbols": ["A", "B"], "default": "A"}],
 "messages": { "bar": {"request": [{"name": "choice", "type": "AorB"}],"response": "null"}}}