diff --git a/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php b/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php
index 0a0732f473..7b1c44674e 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php
@@ -216,10 +216,10 @@ class JsonResponseTest extends \PHPUnit_Framework_TestCase
 
     public function testSetComplexCallback()
     {
-        $response = JsonResponse::fromJsonString('{foo: "bar"}');
+        $response = JsonResponse::create(array('foo' => 'bar'));
         $response->setCallback('ಠ_ಠ["foo"].bar[0]');
 
-        $this->assertEquals('/**/ಠ_ಠ["foo"].bar[0]({foo: "bar"});', $response->getContent());
+        $this->assertEquals('/**/ಠ_ಠ["foo"].bar[0]({"foo":"bar"});', $response->getContent());
     }
 }
 
diff --git a/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php b/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php
index e772c246b2..dd07c08a47 100644
--- a/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php
@@ -116,7 +116,8 @@ class ReflectionCaster
 
         if (isset($a[$prefix.'returnType'])) {
             $v = $a[$prefix.'returnType'];
-            $a[$prefix.'returnType'] = $v instanceof \ReflectionNamedType ? $v->getName() : $v->__toString();
+            $v = $v instanceof \ReflectionNamedType ? $v->getName() : $v->__toString();
+            $a[$prefix.'returnType'] = $a[$prefix.'returnType']->allowsNull() ? '?'.$v : $v;
         }
         if (isset($a[$prefix.'this'])) {
             $a[$prefix.'this'] = new CutStub($a[$prefix.'this']);
@@ -168,21 +169,12 @@ class ReflectionCaster
             'allowsNull' => 'allowsNull',
         ));
 
-        try {
-            if (method_exists($c, 'getType')) {
-                if ($v = $c->getType()) {
-                    $a[$prefix.'typeHint'] = $v instanceof \ReflectionNamedType ? $v->getName() : $v->__toString();
-                }
-            } else {
-                $v = explode(' ', $c->__toString(), 6);
-                if (isset($v[5]) && 0 === strspn($v[4], '.&$')) {
-                    $a[$prefix.'typeHint'] = $v[4];
-                }
-            }
-        } catch (\ReflectionException $e) {
-            if (preg_match('/^Class ([^ ]++) does not exist$/', $e->getMessage(), $m)) {
-                $a[$prefix.'typeHint'] = $m[1];
+        if (method_exists($c, 'getType')) {
+            if ($v = $c->getType()) {
+                $a[$prefix.'typeHint'] = $v instanceof \ReflectionNamedType ? $v->getName() : $v->__toString();
             }
+        } elseif (preg_match('/^(?:[^ ]++ ){4}([a-zA-Z_\x7F-\xFF][^ ]++)/', $c, $v)) {
+            $a[$prefix.'typeHint'] = $v[1];
         }
         if (!isset($a[$prefix.'typeHint'])) {
             unset($a[$prefix.'allowsNull']);