diff --git a/src/Symfony/Component/Config/FileLocator.php b/src/Symfony/Component/Config/FileLocator.php
index 0da2ad636667..71bb5ab0ba30 100644
--- a/src/Symfony/Component/Config/FileLocator.php
+++ b/src/Symfony/Component/Config/FileLocator.php
@@ -31,18 +31,14 @@ public function __construct($paths = array())
     }
 
     /**
-     * Returns a full path for a given file name.
-     *
-     * @param mixed   $name        The file name to locate
-     * @param string  $currentPath The current path
-     * @param bool    $first       Whether to return the first occurrence or an array of filenames
-     *
-     * @return string|array The full path to the file|An array of file paths
-     *
-     * @throws \InvalidArgumentException When file is not found
+     * {@inheritdoc}
      */
     public function locate($name, $currentPath = null, $first = true)
     {
+        if ('' == $name) {
+            throw new \InvalidArgumentException('An empty file name is not valid to be located.');
+        }
+
         if ($this->isAbsolutePath($name)) {
             if (!file_exists($name)) {
                 throw new \InvalidArgumentException(sprintf('The file "%s" does not exist.', $name));
@@ -84,10 +80,10 @@ public function locate($name, $currentPath = null, $first = true)
      */
     private function isAbsolutePath($file)
     {
-        if ($file[0] == '/' || $file[0] == '\\'
+        if ($file[0] === '/' || $file[0] === '\\'
             || (strlen($file) > 3 && ctype_alpha($file[0])
-                && $file[1] == ':'
-                && ($file[2] == '\\' || $file[2] == '/')
+                && $file[1] === ':'
+                && ($file[2] === '\\' || $file[2] === '/')
             )
             || null !== parse_url($file, PHP_URL_SCHEME)
         ) {
diff --git a/src/Symfony/Component/Config/FileLocatorInterface.php b/src/Symfony/Component/Config/FileLocatorInterface.php
index 4287e3d1d0d3..66057982db89 100644
--- a/src/Symfony/Component/Config/FileLocatorInterface.php
+++ b/src/Symfony/Component/Config/FileLocatorInterface.php
@@ -19,11 +19,11 @@ interface FileLocatorInterface
     /**
      * Returns a full path for a given file name.
      *
-     * @param mixed   $name        The file name to locate
-     * @param string  $currentPath The current path
-     * @param bool    $first       Whether to return the first occurrence or an array of filenames
+     * @param string      $name        The file name to locate
+     * @param string|null $currentPath The current path
+     * @param bool        $first       Whether to return the first occurrence or an array of filenames
      *
-     * @return string|array The full path to the file|An array of file paths
+     * @return string|array The full path to the file or an array of file paths
      *
      * @throws \InvalidArgumentException When file is not found
      */
diff --git a/src/Symfony/Component/Config/Loader/DelegatingLoader.php b/src/Symfony/Component/Config/Loader/DelegatingLoader.php
index fa81311422e3..3097878bf0bf 100644
--- a/src/Symfony/Component/Config/Loader/DelegatingLoader.php
+++ b/src/Symfony/Component/Config/Loader/DelegatingLoader.php
@@ -34,14 +34,7 @@ public function __construct(LoaderResolverInterface $resolver)
     }
 
     /**
-     * Loads a resource.
-     *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
-     *
-     * @return mixed
-     *
-     * @throws FileLoaderLoadException if no loader is found.
+     * {@inheritdoc}
      */
     public function load($resource, $type = null)
     {
diff --git a/src/Symfony/Component/Config/Loader/FileLoader.php b/src/Symfony/Component/Config/Loader/FileLoader.php
index 981d16f92bac..b76390bcbb51 100644
--- a/src/Symfony/Component/Config/Loader/FileLoader.php
+++ b/src/Symfony/Component/Config/Loader/FileLoader.php
@@ -22,8 +22,14 @@
  */
 abstract class FileLoader extends Loader
 {
+    /**
+     * @var array
+     */
     protected static $loading = array();
 
+    /**
+     * @var FileLocatorInterface
+     */
     protected $locator;
 
     private $currentDir;
@@ -38,11 +44,21 @@ public function __construct(FileLocatorInterface $locator)
         $this->locator = $locator;
     }
 
+    /**
+     * Sets the current directory.
+     *
+     * @param string $dir
+     */
     public function setCurrentDir($dir)
     {
         $this->currentDir = $dir;
     }
 
+    /**
+     * Returns the file locator used by this loader.
+     *
+     * @return FileLocatorInterface
+     */
     public function getLocator()
     {
         return $this->locator;
@@ -51,10 +67,10 @@ public function getLocator()
     /**
      * Imports a resource.
      *
-     * @param mixed   $resource       A Resource
-     * @param string  $type           The resource type
-     * @param bool    $ignoreErrors   Whether to ignore import errors or not
-     * @param string  $sourceResource The original resource importing the new resource
+     * @param mixed       $resource       A Resource
+     * @param string|null $type           The resource type or null if unknown
+     * @param bool        $ignoreErrors   Whether to ignore import errors or not
+     * @param string|null $sourceResource The original resource importing the new resource
      *
      * @return mixed
      *
diff --git a/src/Symfony/Component/Config/Loader/Loader.php b/src/Symfony/Component/Config/Loader/Loader.php
index 705a6a78e956..de4e127386d8 100644
--- a/src/Symfony/Component/Config/Loader/Loader.php
+++ b/src/Symfony/Component/Config/Loader/Loader.php
@@ -23,9 +23,7 @@ abstract class Loader implements LoaderInterface
     protected $resolver;
 
     /**
-     * Gets the loader resolver.
-     *
-     * @return LoaderResolverInterface A LoaderResolverInterface instance
+     * {@inheritdoc}
      */
     public function getResolver()
     {
@@ -33,9 +31,7 @@ public function getResolver()
     }
 
     /**
-     * Sets the loader resolver.
-     *
-     * @param LoaderResolverInterface $resolver A LoaderResolverInterface instance
+     * {@inheritdoc}
      */
     public function setResolver(LoaderResolverInterface $resolver)
     {
@@ -45,8 +41,8 @@ public function setResolver(LoaderResolverInterface $resolver)
     /**
      * Imports a resource.
      *
-     * @param mixed  $resource A Resource
-     * @param string $type     The resource type
+     * @param mixed       $resource A resource
+     * @param string|null $type     The resource type or null if unknown
      *
      * @return mixed
      */
@@ -58,12 +54,12 @@ public function import($resource, $type = null)
     /**
      * Finds a loader able to load an imported resource.
      *
-     * @param mixed  $resource A Resource
-     * @param string $type     The resource type
+     * @param mixed       $resource A resource
+     * @param string|null $type     The resource type or null if unknown
      *
      * @return LoaderInterface A LoaderInterface instance
      *
-     * @throws FileLoaderLoadException if no loader is found
+     * @throws FileLoaderLoadException If no loader is found
      */
     public function resolve($resource, $type = null)
     {
diff --git a/src/Symfony/Component/Config/Loader/LoaderInterface.php b/src/Symfony/Component/Config/Loader/LoaderInterface.php
index 52d5981e8ea6..dd0a85a6b08c 100644
--- a/src/Symfony/Component/Config/Loader/LoaderInterface.php
+++ b/src/Symfony/Component/Config/Loader/LoaderInterface.php
@@ -21,18 +21,20 @@ interface LoaderInterface
     /**
      * Loads a resource.
      *
-     * @param mixed  $resource The resource
-     * @param string $type     The resource type
+     * @param mixed       $resource The resource
+     * @param string|null $type     The resource type or null if unknown
+     *
+     * @throws \Exception If something went wrong
      */
     public function load($resource, $type = null);
 
     /**
-     * Returns true if this class supports the given resource.
+     * Returns whether this class supports the given resource.
      *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
+     * @param mixed       $resource A resource
+     * @param string|null $type     The resource type or null if unknown
      *
-     * @return bool    true if this class supports the given resource, false otherwise
+     * @return bool True if this class supports the given resource, false otherwise
      */
     public function supports($resource, $type = null);
 
diff --git a/src/Symfony/Component/Config/Loader/LoaderResolver.php b/src/Symfony/Component/Config/Loader/LoaderResolver.php
index 2340fe07f886..e547e8a1d34a 100644
--- a/src/Symfony/Component/Config/Loader/LoaderResolver.php
+++ b/src/Symfony/Component/Config/Loader/LoaderResolver.php
@@ -40,12 +40,7 @@ public function __construct(array $loaders = array())
     }
 
     /**
-     * Returns a loader able to load the resource.
-     *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
-     *
-     * @return LoaderInterface|false A LoaderInterface instance
+     * {@inheritdoc}
      */
     public function resolve($resource, $type = null)
     {
diff --git a/src/Symfony/Component/Config/Loader/LoaderResolverInterface.php b/src/Symfony/Component/Config/Loader/LoaderResolverInterface.php
index 57d878152ab5..40f1a1a63f29 100644
--- a/src/Symfony/Component/Config/Loader/LoaderResolverInterface.php
+++ b/src/Symfony/Component/Config/Loader/LoaderResolverInterface.php
@@ -21,10 +21,10 @@ interface LoaderResolverInterface
     /**
      * Returns a loader able to load the resource.
      *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
+     * @param mixed       $resource A resource
+     * @param string|null $type     The resource type or null if unknown
      *
-     * @return LoaderInterface A LoaderInterface instance
+     * @return LoaderInterface|false The loader or false if none is able to load the resource
      */
     public function resolve($resource, $type = null);
 }
diff --git a/src/Symfony/Component/Config/Resource/DirectoryResource.php b/src/Symfony/Component/Config/Resource/DirectoryResource.php
index a9e4d7614391..f15b81a311c9 100644
--- a/src/Symfony/Component/Config/Resource/DirectoryResource.php
+++ b/src/Symfony/Component/Config/Resource/DirectoryResource.php
@@ -24,8 +24,8 @@ class DirectoryResource implements ResourceInterface, \Serializable
     /**
      * Constructor.
      *
-     * @param string $resource The file path to the resource
-     * @param string $pattern  A pattern to restrict monitored files
+     * @param string      $resource The file path to the resource
+     * @param string|null $pattern  A pattern to restrict monitored files
      */
     public function __construct($resource, $pattern = null)
     {
@@ -34,9 +34,7 @@ public function __construct($resource, $pattern = null)
     }
 
     /**
-     * Returns a string representation of the Resource.
-     *
-     * @return string A string representation of the Resource
+     * {@inheritdoc}
      */
     public function __toString()
     {
@@ -44,26 +42,25 @@ public function __toString()
     }
 
     /**
-     * Returns the resource tied to this Resource.
-     *
-     * @return mixed The resource
+     * {@inheritdoc}
      */
     public function getResource()
     {
         return $this->resource;
     }
 
+    /**
+     * Returns the pattern to restrict monitored files
+     *
+     * @return string|null
+     */
     public function getPattern()
     {
         return $this->pattern;
     }
 
     /**
-     * Returns true if the resource has not been updated since the given timestamp.
-     *
-     * @param int     $timestamp The last time the resource was loaded
-     *
-     * @return bool    true if the resource has not been updated, false otherwise
+     * {@inheritdoc}
      */
     public function isFresh($timestamp)
     {
diff --git a/src/Symfony/Component/Config/Resource/FileResource.php b/src/Symfony/Component/Config/Resource/FileResource.php
index 5cb4bc7078ef..b828e7d37f66 100644
--- a/src/Symfony/Component/Config/Resource/FileResource.php
+++ b/src/Symfony/Component/Config/Resource/FileResource.php
@@ -20,6 +20,9 @@
  */
 class FileResource implements ResourceInterface, \Serializable
 {
+    /**
+     * @var string|false
+     */
     private $resource;
 
     /**
@@ -33,9 +36,7 @@ public function __construct($resource)
     }
 
     /**
-     * Returns a string representation of the Resource.
-     *
-     * @return string A string representation of the Resource
+     * {@inheritdoc}
      */
     public function __toString()
     {
@@ -43,9 +44,7 @@ public function __toString()
     }
 
     /**
-     * Returns the resource tied to this Resource.
-     *
-     * @return mixed The resource
+     * {@inheritdoc}
      */
     public function getResource()
     {
@@ -53,15 +52,11 @@ public function getResource()
     }
 
     /**
-     * Returns true if the resource has not been updated since the given timestamp.
-     *
-     * @param int     $timestamp The last time the resource was loaded
-     *
-     * @return bool    true if the resource has not been updated, false otherwise
+     * {@inheritdoc}
      */
     public function isFresh($timestamp)
     {
-        if (!file_exists($this->resource)) {
+        if (false === $this->resource || !file_exists($this->resource)) {
             return false;
         }
 
diff --git a/src/Symfony/Component/Config/Resource/ResourceInterface.php b/src/Symfony/Component/Config/Resource/ResourceInterface.php
index c0ea9ed7b46d..db03d127a401 100644
--- a/src/Symfony/Component/Config/Resource/ResourceInterface.php
+++ b/src/Symfony/Component/Config/Resource/ResourceInterface.php
@@ -28,14 +28,14 @@ public function __toString();
     /**
      * Returns true if the resource has not been updated since the given timestamp.
      *
-     * @param int     $timestamp The last time the resource was loaded
+     * @param int $timestamp The last time the resource was loaded
      *
-     * @return bool    true if the resource has not been updated, false otherwise
+     * @return bool True if the resource has not been updated, false otherwise
      */
     public function isFresh($timestamp);
 
     /**
-     * Returns the resource tied to this Resource.
+     * Returns the tied resource.
      *
      * @return mixed The resource
      */
diff --git a/src/Symfony/Component/Config/Tests/FileLocatorTest.php b/src/Symfony/Component/Config/Tests/FileLocatorTest.php
index 8e8f442f5e6a..d479f2569f1f 100644
--- a/src/Symfony/Component/Config/Tests/FileLocatorTest.php
+++ b/src/Symfony/Component/Config/Tests/FileLocatorTest.php
@@ -87,6 +87,7 @@ public function testLocate()
 
     /**
      * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage The file "foobar.xml" does not exist
      */
     public function testLocateThrowsAnExceptionIfTheFileDoesNotExists()
     {
@@ -104,4 +105,15 @@ public function testLocateThrowsAnExceptionIfTheFileDoesNotExistsInAbsolutePath(
 
         $loader->locate(__DIR__.'/Fixtures/foobar.xml', __DIR__);
     }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage An empty file name is not valid to be located.
+     */
+    public function testLocateEmpty()
+    {
+        $loader = new FileLocator(array(__DIR__.'/Fixtures'));
+
+        $loader->locate(null, __DIR__);
+    }
 }
diff --git a/src/Symfony/Component/DependencyInjection/Loader/ClosureLoader.php b/src/Symfony/Component/DependencyInjection/Loader/ClosureLoader.php
index 30cbe0ebaf99..a5b4e5ad240e 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/ClosureLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/ClosureLoader.php
@@ -36,23 +36,15 @@ public function __construct(ContainerBuilder $container)
     }
 
     /**
-     * Loads a Closure.
-     *
-     * @param \Closure $closure The resource
-     * @param string   $type    The resource type
+     * {@inheritdoc}
      */
-    public function load($closure, $type = null)
+    public function load($resource, $type = null)
     {
-        call_user_func($closure, $this->container);
+        call_user_func($resource, $this->container);
     }
 
     /**
-     * Returns true if this class supports the given resource.
-     *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
-     *
-     * @return bool    true if this class supports the given resource, false otherwise
+     * {@inheritdoc}
      */
     public function supports($resource, $type = null)
     {
diff --git a/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php
index ad437b5138d4..d71eecf74156 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php
@@ -27,8 +27,8 @@ abstract class FileLoader extends BaseFileLoader
     /**
      * Constructor.
      *
-     * @param ContainerBuilder $container A ContainerBuilder instance
-     * @param FileLocatorInterface      $locator   A FileLocator instance
+     * @param ContainerBuilder     $container A ContainerBuilder instance
+     * @param FileLocatorInterface $locator   A FileLocator instance
      */
     public function __construct(ContainerBuilder $container, FileLocatorInterface $locator)
     {
diff --git a/src/Symfony/Component/DependencyInjection/Loader/IniFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/IniFileLoader.php
index 189eaa5fde15..16ddf87f8511 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/IniFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/IniFileLoader.php
@@ -22,22 +22,17 @@
 class IniFileLoader extends FileLoader
 {
     /**
-     * Loads a resource.
-     *
-     * @param mixed  $file The resource
-     * @param string $type The resource type
-     *
-     * @throws InvalidArgumentException When ini file is not valid
+     * {@inheritdoc}
      */
-    public function load($file, $type = null)
+    public function load($resource, $type = null)
     {
-        $path = $this->locator->locate($file);
+        $path = $this->locator->locate($resource);
 
         $this->container->addResource(new FileResource($path));
 
         $result = parse_ini_file($path, true);
         if (false === $result || array() === $result) {
-            throw new InvalidArgumentException(sprintf('The "%s" file is not valid.', $file));
+            throw new InvalidArgumentException(sprintf('The "%s" file is not valid.', $resource));
         }
 
         if (isset($result['parameters']) && is_array($result['parameters'])) {
@@ -48,12 +43,7 @@ public function load($file, $type = null)
     }
 
     /**
-     * Returns true if this class supports the given resource.
-     *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
-     *
-     * @return bool    true if this class supports the given resource, false otherwise
+     * {@inheritdoc}
      */
     public function supports($resource, $type = null)
     {
diff --git a/src/Symfony/Component/DependencyInjection/Loader/PhpFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/PhpFileLoader.php
index f3139ad70a82..08c1d9af4f65 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/PhpFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/PhpFileLoader.php
@@ -24,18 +24,15 @@
 class PhpFileLoader extends FileLoader
 {
     /**
-     * Loads a PHP file.
-     *
-     * @param mixed  $file The resource
-     * @param string $type The resource type
+     * {@inheritdoc}
      */
-    public function load($file, $type = null)
+    public function load($resource, $type = null)
     {
         // the container and loader variables are exposed to the included file below
         $container = $this->container;
         $loader = $this;
 
-        $path = $this->locator->locate($file);
+        $path = $this->locator->locate($resource);
         $this->setCurrentDir(dirname($path));
         $this->container->addResource(new FileResource($path));
 
@@ -43,12 +40,7 @@ public function load($file, $type = null)
     }
 
     /**
-     * Returns true if this class supports the given resource.
-     *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
-     *
-     * @return bool    true if this class supports the given resource, false otherwise
+     * {@inheritdoc}
      */
     public function supports($resource, $type = null)
     {
diff --git a/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
index 4147a403cdac..24104fd2ccdd 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
@@ -30,14 +30,11 @@
 class XmlFileLoader extends FileLoader
 {
     /**
-     * Loads an XML file.
-     *
-     * @param mixed  $file The resource
-     * @param string $type The resource type
+     * {@inheritdoc}
      */
-    public function load($file, $type = null)
+    public function load($resource, $type = null)
     {
-        $path = $this->locator->locate($file);
+        $path = $this->locator->locate($resource);
 
         $xml = $this->parseFile($path);
         $xml->registerXPathNamespace('container', 'http://symfony.com/schema/dic/services');
@@ -61,12 +58,7 @@ public function load($file, $type = null)
     }
 
     /**
-     * Returns true if this class supports the given resource.
-     *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
-     *
-     * @return bool    true if this class supports the given resource, false otherwise
+     * {@inheritdoc}
      */
     public function supports($resource, $type = null)
     {
diff --git a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
index 8fee1bfefadc..a96cc39c06ac 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
@@ -32,14 +32,11 @@ class YamlFileLoader extends FileLoader
     private $yamlParser;
 
     /**
-     * Loads a Yaml file.
-     *
-     * @param mixed  $file The resource
-     * @param string $type The resource type
+     * {@inheritdoc}
      */
-    public function load($file, $type = null)
+    public function load($resource, $type = null)
     {
-        $path = $this->locator->locate($file);
+        $path = $this->locator->locate($resource);
 
         $content = $this->loadFile($path);
 
@@ -56,7 +53,7 @@ public function load($file, $type = null)
         // parameters
         if (isset($content['parameters'])) {
             if (!is_array($content['parameters'])) {
-                throw new InvalidArgumentException(sprintf('The "parameters" key should contain an array in %s. Check your YAML syntax.', $file));
+                throw new InvalidArgumentException(sprintf('The "parameters" key should contain an array in %s. Check your YAML syntax.', $resource));
             }
 
             foreach ($content['parameters'] as $key => $value) {
@@ -68,16 +65,11 @@ public function load($file, $type = null)
         $this->loadFromExtensions($content);
 
         // services
-        $this->parseDefinitions($content, $file);
+        $this->parseDefinitions($content, $resource);
     }
 
     /**
-     * Returns true if this class supports the given resource.
-     *
-     * @param mixed  $resource A resource
-     * @param string $type     The resource type
-     *
-     * @return bool    true if this class supports the given resource, false otherwise
+     * {@inheritdoc}
      */
     public function supports($resource, $type = null)
     {
diff --git a/src/Symfony/Component/HttpKernel/Config/FileLocator.php b/src/Symfony/Component/HttpKernel/Config/FileLocator.php
index 47b543c15eeb..169c9ad6e502 100644
--- a/src/Symfony/Component/HttpKernel/Config/FileLocator.php
+++ b/src/Symfony/Component/HttpKernel/Config/FileLocator.php
@@ -47,7 +47,7 @@ public function __construct(KernelInterface $kernel, $path = null, array $paths
      */
     public function locate($file, $currentPath = null, $first = true)
     {
-        if ('@' === $file[0]) {
+        if (isset($file[0]) && '@' === $file[0]) {
             return $this->kernel->locateResource($file, $this->path, $first);
         }