diff --git a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/CollectionProcessor.java b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/CollectionProcessor.java
index bf45c3ff4..2d6f1f50d 100644
--- a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/CollectionProcessor.java
+++ b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/CollectionProcessor.java
@@ -18,12 +18,13 @@
  */
 package org.apache.olingo.server.api.processor;
 
+import org.apache.olingo.commons.api.format.ContentType;
 import org.apache.olingo.server.api.ODataRequest;
 import org.apache.olingo.server.api.ODataResponse;
 import org.apache.olingo.server.api.uri.UriInfo;
 
 public interface CollectionProcessor extends Processor {
 
-  void readCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, String format);
+  void readCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType requestedContentType);
 
 }
diff --git a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/DefaultProcessor.java b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/DefaultProcessor.java
index 9251c73c4..97821f1e7 100644
--- a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/DefaultProcessor.java
+++ b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/DefaultProcessor.java
@@ -21,8 +21,8 @@ package org.apache.olingo.server.api.processor;
 import java.io.InputStream;
 
 import org.apache.olingo.commons.api.edm.Edm;
+import org.apache.olingo.commons.api.format.ContentType;
 import org.apache.olingo.commons.api.format.ODataFormat;
-import org.apache.olingo.commons.api.http.HttpContentType;
 import org.apache.olingo.commons.api.http.HttpHeader;
 import org.apache.olingo.server.api.OData;
 import org.apache.olingo.server.api.ODataRequest;
@@ -43,7 +43,7 @@ public class DefaultProcessor implements MetadataProcessor, ServiceDocumentProce
 
   @Override
   public void readServiceDocument(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-      final String format) {
+      final ContentType requestedContentType) {
     ODataSerializer serializer;
     InputStream responseEntity;
 
@@ -51,22 +51,22 @@ public class DefaultProcessor implements MetadataProcessor, ServiceDocumentProce
     responseEntity = serializer.serviceDocument(edm, request.getRawBaseUri());
 
     response.setStatusCode(200);
-    response.setHeader(HttpHeader.CONTENT_TYPE, HttpContentType.APPLICATION_JSON);
     response.setContent(responseEntity);
+    response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
 
   }
 
   @Override
   public void readMetadata(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-      final String format) {
+      final ContentType requestedContentType) {
     ODataSerializer serializer;
     InputStream responseEntity;
 
     serializer = odata.createSerializer(ODataFormat.XML);
     responseEntity = serializer.metadataDocument(edm);
     response.setStatusCode(200);
-    response.setHeader(HttpHeader.CONTENT_TYPE, HttpContentType.APPLICATION_XML);
     response.setContent(responseEntity);
+    response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
   }
 
 }
diff --git a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/EntityProcessor.java b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/EntityProcessor.java
index b0b9476e9..a6ec6c200 100644
--- a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/EntityProcessor.java
+++ b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/EntityProcessor.java
@@ -18,11 +18,13 @@
  */
 package org.apache.olingo.server.api.processor;
 
+import org.apache.olingo.commons.api.format.ContentType;
 import org.apache.olingo.server.api.ODataRequest;
 import org.apache.olingo.server.api.ODataResponse;
 import org.apache.olingo.server.api.uri.UriInfo;
 
 public interface EntityProcessor extends Processor {
 
-  void readEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo, String format);
+  void readEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType format);
+  
 }
diff --git a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/MetadataProcessor.java b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/MetadataProcessor.java
index 89f8e5303..ed187ea1a 100644
--- a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/MetadataProcessor.java
+++ b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/MetadataProcessor.java
@@ -18,11 +18,12 @@
  */
 package org.apache.olingo.server.api.processor;
 
+import org.apache.olingo.commons.api.format.ContentType;
 import org.apache.olingo.server.api.ODataRequest;
 import org.apache.olingo.server.api.ODataResponse;
 import org.apache.olingo.server.api.uri.UriInfo;
 
 public interface MetadataProcessor extends Processor {
 
-  void readMetadata(ODataRequest request, ODataResponse response, UriInfo uriInfo, String format);
+  void readMetadata(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType requestedContentType);
 }
diff --git a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/ServiceDocumentProcessor.java b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/ServiceDocumentProcessor.java
index a1ef6685d..dd90b38de 100644
--- a/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/ServiceDocumentProcessor.java
+++ b/lib/server-api/src/main/java/org/apache/olingo/server/api/processor/ServiceDocumentProcessor.java
@@ -18,12 +18,14 @@
  */
 package org.apache.olingo.server.api.processor;
 
+import org.apache.olingo.commons.api.format.ContentType;
 import org.apache.olingo.server.api.ODataRequest;
 import org.apache.olingo.server.api.ODataResponse;
 import org.apache.olingo.server.api.uri.UriInfo;
 
 public interface ServiceDocumentProcessor extends Processor {
 
-  void readServiceDocument(ODataRequest request, ODataResponse response, UriInfo uriInfo, String format);
+  void readServiceDocument(ODataRequest request, ODataResponse response, UriInfo uriInfo,
+      ContentType requestedContentType);
 
 }
diff --git a/lib/server-core/src/main/java/org/apache/olingo/server/core/ODataHandler.java b/lib/server-core/src/main/java/org/apache/olingo/server/core/ODataHandler.java
index 36a52a882..b8f7bbd52 100644
--- a/lib/server-core/src/main/java/org/apache/olingo/server/core/ODataHandler.java
+++ b/lib/server-core/src/main/java/org/apache/olingo/server/core/ODataHandler.java
@@ -84,7 +84,7 @@ public class ODataHandler {
         requestedContentType =
             ContentNegotiator.doContentNegotiation(uriInfo.getFormatOption(), request, mp, MetadataProcessor.class);
 
-        mp.readMetadata(request, response, uriInfo, requestedContentType.toContentTypeString());
+        mp.readMetadata(request, response, uriInfo, requestedContentType);
         break;
       case service:
         if ("".equals(request.getRawODataPath())) {
@@ -97,7 +97,7 @@ public class ODataHandler {
               ContentNegotiator.doContentNegotiation(uriInfo.getFormatOption(), request, sdp,
                   ServiceDocumentProcessor.class);
 
-          sdp.readServiceDocument(request, response, uriInfo, requestedContentType.toContentTypeString());
+          sdp.readServiceDocument(request, response, uriInfo, requestedContentType);
         }
         break;
       case resource:
@@ -129,7 +129,7 @@ public class ODataHandler {
           requestedContentType =
               ContentNegotiator.doContentNegotiation(uriInfo.getFormatOption(), request, cp, CollectionProcessor.class);
 
-          cp.readCollection(request, response, uriInfo, requestedContentType.toContentTypeString());
+          cp.readCollection(request, response, uriInfo, requestedContentType);
         } else {
           throw new ODataRuntimeException("not implemented");
         }
@@ -140,7 +140,7 @@ public class ODataHandler {
           requestedContentType =
               ContentNegotiator.doContentNegotiation(uriInfo.getFormatOption(), request, ep, EntityProcessor.class);
 
-          ep.readEntity(request, response, uriInfo, requestedContentType.toContentTypeString());
+          ep.readEntity(request, response, uriInfo, requestedContentType);
         } else {
           throw new ODataRuntimeException("not implemented");
         }
@@ -154,7 +154,7 @@ public class ODataHandler {
           requestedContentType =
               ContentNegotiator.doContentNegotiation(uriInfo.getFormatOption(), request, cp, CollectionProcessor.class);
 
-          cp.readCollection(request, response, uriInfo, requestedContentType.toContentTypeString());
+          cp.readCollection(request, response, uriInfo, requestedContentType);
         } else {
           throw new ODataRuntimeException("not implemented");
         }
@@ -165,7 +165,7 @@ public class ODataHandler {
           requestedContentType =
               ContentNegotiator.doContentNegotiation(uriInfo.getFormatOption(), request, ep, EntityProcessor.class);
 
-          ep.readEntity(request, response, uriInfo, requestedContentType.toContentTypeString());
+          ep.readEntity(request, response, uriInfo, requestedContentType);
         } else {
           throw new ODataRuntimeException("not implemented");
         }
diff --git a/lib/server-core/src/test/java/org/apache/olingo/server/core/ContentNegotiatorTest.java b/lib/server-core/src/test/java/org/apache/olingo/server/core/ContentNegotiatorTest.java
index 10df086d7..cc766f48a 100644
--- a/lib/server-core/src/test/java/org/apache/olingo/server/core/ContentNegotiatorTest.java
+++ b/lib/server-core/src/test/java/org/apache/olingo/server/core/ContentNegotiatorTest.java
@@ -214,20 +214,20 @@ public class ContentNegotiatorTest {
 
     @Override
     public void readServiceDocument(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-        final String format) {
-      response.setHeader(HttpHeader.CONTENT_TYPE, format);
+        final ContentType format) {
+      response.setHeader(HttpHeader.CONTENT_TYPE, format.toContentTypeString());
     }
 
     @Override
     public void readCollection(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-        final String format) {
-      response.setHeader(HttpHeader.CONTENT_TYPE, format);
+        final ContentType requestedContentType) {
+      response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
     }
 
     @Override
     public void readMetadata(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-        final String format) {
-      response.setHeader(HttpHeader.CONTENT_TYPE, format);
+        final ContentType requestedContentType) {
+      response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
     }
   }
 }
diff --git a/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/SampleJsonProcessor.java b/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/SampleJsonProcessor.java
index e7d67173c..b3dc02de1 100644
--- a/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/SampleJsonProcessor.java
+++ b/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/SampleJsonProcessor.java
@@ -30,6 +30,7 @@ import org.apache.olingo.commons.api.edm.Edm;
 import org.apache.olingo.commons.api.edm.FullQualifiedName;
 import org.apache.olingo.commons.api.format.ContentType;
 import org.apache.olingo.commons.api.format.ODataFormat;
+import org.apache.olingo.commons.api.http.HttpHeader;
 import org.apache.olingo.commons.api.http.HttpStatusCode;
 import org.apache.olingo.commons.core.data.EntityImpl;
 import org.apache.olingo.commons.core.data.EntitySetImpl;
@@ -58,7 +59,7 @@ public class SampleJsonProcessor implements CollectionProcessor, EntityProcessor
 
   @Override
   public void readCollection(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-      final String format) {
+      final ContentType requestedContentType) {
     long time = System.nanoTime();
 
     EntitySet entitySet = createEntitySet();
@@ -74,12 +75,12 @@ public class SampleJsonProcessor implements CollectionProcessor, EntityProcessor
     LOG.info("Finished in " + (System.nanoTime() - time) / 1000 + " microseconds");
 
     response.setStatusCode(HttpStatusCode.OK.getStatusCode());
-    response.setHeader("Content-Type", ContentType.APPLICATION_JSON.toContentTypeString());
+    response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
   }
 
   @Override
   public void readEntity(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-      final String format) {
+      final ContentType requestedContentType) {
     long time = System.nanoTime();
     Entity entity = createEntity();
 
@@ -94,7 +95,7 @@ public class SampleJsonProcessor implements CollectionProcessor, EntityProcessor
     LOG.info("Finished in " + (System.nanoTime() - time) / 1000 + " microseconds");
 
     response.setStatusCode(HttpStatusCode.OK.getStatusCode());
-    response.setHeader("Content-Type", ContentType.APPLICATION_JSON.toContentTypeString());
+    response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
   }
 
   protected Entity createEntity() {
diff --git a/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/TechnicalProcessor.java b/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/TechnicalProcessor.java
index b3c671c12..7c5a267c1 100644
--- a/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/TechnicalProcessor.java
+++ b/lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/TechnicalProcessor.java
@@ -21,6 +21,8 @@ package org.apache.olingo.server.tecsvc.processor;
 import java.io.ByteArrayInputStream;
 
 import org.apache.olingo.commons.api.edm.Edm;
+import org.apache.olingo.commons.api.format.ContentType;
+import org.apache.olingo.commons.api.http.HttpHeader;
 import org.apache.olingo.server.api.OData;
 import org.apache.olingo.server.api.ODataRequest;
 import org.apache.olingo.server.api.ODataResponse;
@@ -38,15 +40,17 @@ public class TechnicalProcessor implements CollectionProcessor, EntityProcessor
 
   @Override
   public void readEntity(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-      final String format) {
+      final ContentType requestedContentType) {
     response.setContent(new ByteArrayInputStream("Entity".getBytes()));
     response.setStatusCode(200);
+    response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
   }
 
   @Override
   public void readCollection(final ODataRequest request, final ODataResponse response, final UriInfo uriInfo,
-      final String format) {
+      final ContentType requestedContentType) {
     response.setContent(new ByteArrayInputStream("EntitySet".getBytes()));
     response.setStatusCode(200);
+    response.setHeader(HttpHeader.CONTENT_TYPE, requestedContentType.toContentTypeString());
   }
 }