add plaintext test to java/grizzly-jersey (#2183)

frameworks/Java/grizzly-jersey/benchmark_config.json

@@ -7,6 +7,7 @@
       "db_url": "/db?single=true",
       "query_url": "/db?queries=",
       "fortune_url": "/fortunes",
+      "plaintext_url": "/plaintext",
       "port": 8080,
       "approach": "Realistic",
       "classification": "Micro",

frameworks/Java/grizzly-jersey/src/main/java/hello/DbResource.java

@@ -32,7 +32,7 @@ public class DbResource {
   private SessionFactory sessionFactory;
   
   @GET
-  @Produces(APPLICATION_JSON + "; charset=utf-8")
+  @Produces(APPLICATION_JSON)
   public Object db(@QueryParam("queries") String queryParam, @QueryParam("single") boolean isSingle)
       throws ExecutionException, InterruptedException {
 

frameworks/Java/grizzly-jersey/src/main/java/hello/JsonResource.java

@@ -16,7 +16,7 @@ import com.sun.jersey.spi.resource.Singleton;
 public class JsonResource {
   
   @GET
-  @Produces(APPLICATION_JSON + "; charset=utf-8")
+  @Produces(APPLICATION_JSON)
   public Object json() {
     Map<String, String> data = new HashMap<String, String>(1);
     data.put("message", "Hello, World!");

frameworks/Java/grizzly-jersey/src/main/java/hello/PlaintextResource.java

@@ -0,0 +1,19 @@
+package hello;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+
+import com.sun.jersey.spi.resource.Singleton;
+
+@Singleton
+@Path("/plaintext")
+public class PlaintextResource {
+
+  @GET
+  @Produces("text/plain")
+  public Object plaintext() {
+    String data = "Hello, World!";
+    return data;
+  }
+}