diff --git a/src/Symfony/Component/HttpKernel/DataCollector/RequestDataCollector.php b/src/Symfony/Component/HttpKernel/DataCollector/RequestDataCollector.php
index 9a499a737a..7929cfc614 100644
--- a/src/Symfony/Component/HttpKernel/DataCollector/RequestDataCollector.php
+++ b/src/Symfony/Component/HttpKernel/DataCollector/RequestDataCollector.php
@@ -12,10 +12,8 @@
 namespace Symfony\Component\HttpKernel\DataCollector;
 
 use Symfony\Component\HttpFoundation\ParameterBag;
-use Symfony\Component\HttpFoundation\HeaderBag;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
-use Symfony\Component\HttpFoundation\ResponseHeaderBag;
 use Symfony\Component\HttpKernel\KernelEvents;
 use Symfony\Component\HttpKernel\Event\FilterControllerEvent;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
@@ -40,12 +38,8 @@ class RequestDataCollector extends DataCollector implements EventSubscriberInter
     public function collect(Request $request, Response $response, \Exception $exception = null)
     {
         $responseHeaders = $response->headers->all();
-        $cookies = array();
         foreach ($response->headers->getCookies() as $cookie) {
-            $cookies[] = $this->getCookieHeader($cookie->getName(), $cookie->getValue(), $cookie->getExpiresTime(), $cookie->getPath(), $cookie->getDomain(), $cookie->isSecure(), $cookie->isHttpOnly());
-        }
-        if (count($cookies) > 0) {
-            $responseHeaders['Set-Cookie'] = $cookies;
+            $responseHeaders['set-cookie'][] = (string) $cookie;
         }
 
         // attributes are serialized and as they can be anything, they need to be converted to strings.
@@ -121,6 +115,18 @@ class RequestDataCollector extends DataCollector implements EventSubscriberInter
             $this->data['request_request']['_password'] = '******';
         }
 
+        foreach ($this->data as $key => $value) {
+            if (!is_array($value)) {
+                continue;
+            }
+            if ('request_headers' === $key || 'response_headers' === $key) {
+                $value = array_map(function ($v) { return isset($v[0]) && !isset($v[1]) ? $v[0] : $v; }, $value);
+            }
+            if ('request_server' !== $key && 'request_cookies' !== $key) {
+                $this->data[$key] = $value;
+            }
+        }
+
         if (isset($this->controllers[$request])) {
             $controller = $this->controllers[$request];
             if (is_array($controller)) {
@@ -183,7 +189,7 @@ class RequestDataCollector extends DataCollector implements EventSubscriberInter
 
     public function getRequestHeaders()
     {
-        return new HeaderBag($this->data['request_headers']);
+        return new ParameterBag($this->data['request_headers']);
     }
 
     public function getRequestServer()
@@ -203,7 +209,7 @@ class RequestDataCollector extends DataCollector implements EventSubscriberInter
 
     public function getResponseHeaders()
     {
-        return new ResponseHeaderBag($this->data['response_headers']);
+        return new ParameterBag($this->data['response_headers']);
     }
 
     public function getSessionMetadata()
@@ -302,41 +308,4 @@ class RequestDataCollector extends DataCollector implements EventSubscriberInter
     {
         return 'request';
     }
-
-    private function getCookieHeader($name, $value, $expires, $path, $domain, $secure, $httponly)
-    {
-        $cookie = sprintf('%s=%s', $name, urlencode($value));
-
-        if (0 !== $expires) {
-            if (is_numeric($expires)) {
-                $expires = (int) $expires;
-            } elseif ($expires instanceof \DateTime) {
-                $expires = $expires->getTimestamp();
-            } else {
-                $tmp = strtotime($expires);
-                if (false === $tmp || -1 == $tmp) {
-                    throw new \InvalidArgumentException(sprintf('The "expires" cookie parameter is not valid (%s).', $expires));
-                }
-                $expires = $tmp;
-            }
-
-            $cookie .= '; expires='.str_replace('+0000', '', \DateTime::createFromFormat('U', $expires, new \DateTimeZone('GMT'))->format('D, d-M-Y H:i:s T'));
-        }
-
-        if ($domain) {
-            $cookie .= '; domain='.$domain;
-        }
-
-        $cookie .= '; path='.$path;
-
-        if ($secure) {
-            $cookie .= '; secure';
-        }
-
-        if ($httponly) {
-            $cookie .= '; httponly';
-        }
-
-        return $cookie;
-    }
 }
diff --git a/src/Symfony/Component/HttpKernel/Tests/DataCollector/RequestDataCollectorTest.php b/src/Symfony/Component/HttpKernel/Tests/DataCollector/RequestDataCollectorTest.php
index 2eb1c41e8d..3a0ab50321 100644
--- a/src/Symfony/Component/HttpKernel/Tests/DataCollector/RequestDataCollectorTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/DataCollector/RequestDataCollectorTest.php
@@ -31,7 +31,7 @@ class RequestDataCollectorTest extends \PHPUnit_Framework_TestCase
         $attributes = $c->getRequestAttributes();
 
         $this->assertSame('request', $c->getName());
-        $this->assertInstanceOf('Symfony\Component\HttpFoundation\HeaderBag', $c->getRequestHeaders());
+        $this->assertInstanceOf('Symfony\Component\HttpFoundation\ParameterBag', $c->getRequestHeaders());
         $this->assertInstanceOf('Symfony\Component\HttpFoundation\ParameterBag', $c->getRequestServer());
         $this->assertInstanceOf('Symfony\Component\HttpFoundation\ParameterBag', $c->getRequestCookies());
         $this->assertInstanceOf('Symfony\Component\HttpFoundation\ParameterBag', $attributes);
@@ -45,7 +45,7 @@ class RequestDataCollectorTest extends \PHPUnit_Framework_TestCase
         $this->assertRegExp('/Resource\(stream#\d+\)/', $attributes->get('resource'));
         $this->assertSame('Object(stdClass)', $attributes->get('object'));
 
-        $this->assertInstanceOf('Symfony\Component\HttpFoundation\HeaderBag', $c->getResponseHeaders());
+        $this->assertInstanceOf('Symfony\Component\HttpFoundation\ParameterBag', $c->getResponseHeaders());
         $this->assertSame('OK', $c->getStatusText());
         $this->assertSame(200, $c->getStatusCode());
         $this->assertSame('application/json', $c->getContentType());