Issue #648 - For /db request always return JSON object, for /db?queries=xys return JSON array

wicket/src/main/java/hellowicket/HelloDbResponse.java

@@ -4,6 +4,7 @@ import java.io.IOException;
 import java.util.concurrent.ThreadLocalRandom;
 
 import org.apache.wicket.request.resource.AbstractResource;
+import org.apache.wicket.util.string.StringValue;
 import org.hibernate.IdentifierLoadAccess;
 import org.hibernate.Session;
 
@@ -20,7 +21,8 @@ public class HelloDbResponse extends AbstractResource
 
   protected ResourceResponse newResourceResponse(Attributes attributes)
   {
-    int qs = attributes.getRequest().getQueryParameters().getParameterValue("queries").toInt(1);
+    final StringValue queriesParam = attributes.getRequest().getQueryParameters().getParameterValue("queries");
+    int qs = queriesParam.toInt(1);
     if (qs < 1)
     {
       qs = 1;
@@ -53,12 +55,14 @@ public class HelloDbResponse extends AbstractResource
         try
         {
           String data;
-          if (queries == 1)
+          if (queriesParam.isNull())
           {
+              // request to /db should return JSON object
               data = HelloDbResponse.mapper.writeValueAsString(worlds[0]);
           }
           else
           {
+              // request to /db?queries=xyz should return JSON array (issue #648)
               data = HelloDbResponse.mapper.writeValueAsString(worlds);
           }
           attributes.getResponse().write(data);