diff --git a/core/lib/Drupal/Core/DrupalBundle.php b/core/lib/Drupal/Core/CoreBundle.php
similarity index 91%
rename from core/lib/Drupal/Core/DrupalBundle.php
rename to core/lib/Drupal/Core/CoreBundle.php
index acd16279b1f4..04ec59f3e8e0 100644
--- a/core/lib/Drupal/Core/DrupalBundle.php
+++ b/core/lib/Drupal/Core/CoreBundle.php
@@ -9,10 +9,14 @@ use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 use Symfony\Component\DependencyInjection\Compiler\PassConfig;
 
-class DrupalBundle extends Bundle
+/**
+ * This is where Drupal core registers all of its services to the Dependency
+ * Injection Container. Modules wishing to register services to the container
+ * should extend Symfony's Bundle class directly, not this class.
+ */
+class CoreBundle extends Bundle
 {
-  public function build(ContainerBuilder $container)
-  {
+  public function build(ContainerBuilder $container) {
     $container->register('dispatcher', 'Symfony\Component\EventDispatcher\ContainerAwareEventDispatcher')
       ->addArgument(new Reference('service_container'));
     $container->register('resolver', 'Symfony\Component\HttpKernel\Controller\ControllerResolver');
@@ -57,6 +61,5 @@ class DrupalBundle extends Bundle
 
     // Add a compiler pass for registering event subscribers.
     $container->addCompilerPass(new RegisterKernelListenersPass(), PassConfig::TYPE_AFTER_REMOVING);
-
   }
 }
diff --git a/core/lib/Drupal/Core/DependencyInjection/Compiler/RegisterKernelListenersPass.php b/core/lib/Drupal/Core/DependencyInjection/Compiler/RegisterKernelListenersPass.php
index 79fbe7cdbc39..55343dc3b004 100644
--- a/core/lib/Drupal/Core/DependencyInjection/Compiler/RegisterKernelListenersPass.php
+++ b/core/lib/Drupal/Core/DependencyInjection/Compiler/RegisterKernelListenersPass.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\DependencyInjection\Compiler;
 
+use ReflectionClass;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
 
@@ -25,7 +26,7 @@ class RegisterKernelListenersPass implements CompilerPassInterface
       // We must assume that the class value has been correcly filled, even if the service is created by a factory
       $class = $container->getDefinition($id)->getClass();
 
-      $refClass = new \ReflectionClass($class);
+      $refClass = new ReflectionClass($class);
       $interface = 'Symfony\Component\EventDispatcher\EventSubscriberInterface';
       if (!$refClass->implementsInterface($interface)) {
         throw new \InvalidArgumentException(sprintf('Service "%s" must implement interface "%s".', $id, $interface));
diff --git a/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php b/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php
index fe4541fc98d4..75a31bf82daa 100644
--- a/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php
+++ b/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php
@@ -18,21 +18,16 @@ use Symfony\Component\DependencyInjection\ParameterBag\FrozenParameterBag;
  */
 class ContainerBuilder extends BaseContainerBuilder {
 
-  public function addCompilerPass(CompilerPassInterface $pass, $type = PassConfig::TYPE_BEFORE_OPTIMIZATION)
-  {
-    if (!isset($this->compiler) || null === $this->compiler) {
-      $this->compiler = new Compiler();
-    }
+  public function __construct() {
+    parent::__construct();
+    $this->compiler = new Compiler();
+  }
 
+  public function addCompilerPass(CompilerPassInterface $pass, $type = PassConfig::TYPE_BEFORE_OPTIMIZATION) {
     $this->compiler->addPass($pass, $type);
   }
 
-  public function compile()
-  {
-    if (null === $this->compiler) {
-      $this->compiler = new Compiler();
-    }
-
+  public function compile() {
     $this->compiler->compile($this);
     $this->parameterBag->resolve();
     // TODO: The line below is commented out because there is code that calls
diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index 283e59cf532b..0c19a6bdc7a0 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Core;
 
-use Drupal\Core\DrupalBundle;
+use Drupal\Core\CoreBundle;
 use Symfony\Component\HttpKernel\Kernel;
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Symfony\Component\Config\Loader\LoaderInterface;
@@ -18,10 +18,9 @@ use Symfony\Component\DependencyInjection\ParameterBag\ParameterBag;
  */
 class DrupalKernel extends Kernel {
 
-  public function registerBundles()
-  {
+  public function registerBundles() {
     $bundles = array(
-      new DrupalBundle(),
+      new CoreBundle(),
     );
 
     // Rather than bootstrapping to a higher phase prior to booting the Kernel, which
@@ -47,8 +46,7 @@ class DrupalKernel extends Kernel {
   /**
    * Initializes the service container.
    */
-  protected function initializeContainer()
-  {
+  protected function initializeContainer() {
     $this->container = $this->buildContainer();
     $this->container->set('kernel', $this);
     drupal_container($this->container);
@@ -59,8 +57,7 @@ class DrupalKernel extends Kernel {
    *
    * @return ContainerBuilder The compiled service container
    */
-  protected function buildContainer()
-  {
+  protected function buildContainer() {
     $container = $this->getContainerBuilder();
 
     if ($bootstrap_container = drupal_container()) {
@@ -73,19 +70,16 @@ class DrupalKernel extends Kernel {
     return $container;
   }
 
-
   /**
    * Gets a new ContainerBuilder instance used to build the service container.
    *
    * @return ContainerBuilder
    */
-  protected function getContainerBuilder()
-  {
+  protected function getContainerBuilder() {
     return new ContainerBuilder(new ParameterBag($this->getKernelParameters()));
   }
 
-  public function registerContainerConfiguration(LoaderInterface $loader)
-  {
+  public function registerContainerConfiguration(LoaderInterface $loader) {
     // We have to define this method because it's not defined in the base class
     // but is part of the KernelInterface interface. However, the LoaderInterface
     // class is part of the config component, which we are not using, so this