THRIFT-947. java: Provide a helper method to determine the TProtocol used to serialize some data.

Patch: Mathias Herberts

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@1024455 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/test/ThriftTest.thrift b/test/ThriftTest.thrift
index 66ec2b5..ce324ef 100644
--- a/test/ThriftTest.thrift
+++ b/test/ThriftTest.thrift
@@ -187,3 +187,7 @@
        1: list<string> strings;
        2: string hello;
 }
+
+struct GuessProtocolStruct {
+  7: map<string,string> map_field,
+}