diff --git a/framework/YiiBase.php b/framework/YiiBase.php
index be59c16..464bcea 100644
--- a/framework/YiiBase.php
+++ b/framework/YiiBase.php
@@ -65,7 +65,7 @@ class YiiBase
 	/**
 	 * @var yii\base\Application the application instance
 	 */
-	public static $application;
+	public static $app;
 	/**
 	 * @var array registered path aliases
 	 * @see getAlias
@@ -125,8 +125,8 @@ class YiiBase
 	 *
 	 * To import a class or a directory, one can use either path alias or class name (can be namespaced):
 	 *
-	 *  - `@application/components/GoogleMap`: importing the `GoogleMap` class with a path alias;
-	 *  - `@application/components/*`: importing the whole `components` directory with a path alias;
+	 *  - `@app/components/GoogleMap`: importing the `GoogleMap` class with a path alias;
+	 *  - `@app/components/*`: importing the whole `components` directory with a path alias;
 	 *  - `GoogleMap`: importing the `GoogleMap` class with a class name. [[autoload()]] will be used
 	 *  when this class is used for the first time.
 	 *
@@ -262,6 +262,7 @@ class YiiBase
 	 *
 	 * @param string $className class name
 	 * @return boolean whether the class has been loaded successfully
+	 * @throws Exception if the class file does not exist
 	 */
 	public static function autoload($className)
 	{
@@ -322,12 +323,12 @@ class YiiBase
 	 * the class. For example,
 	 *
 	 * - `\app\components\GoogleMap`: fully-qualified namespaced class.
-	 * - `@application/components/GoogleMap`: an alias
+	 * - `@app/components/GoogleMap`: an alias
 	 *
 	 * Below are some usage examples:
 	 *
 	 * ~~~
-	 * $object = \Yii::createObject('@application/components/GoogleMap');
+	 * $object = \Yii::createObject('@app/components/GoogleMap');
 	 * $object = \Yii::createObject(array(
 	 *     'class' => '\app\components\GoogleMap',
 	 *     'apiKey' => 'xyz',
@@ -520,6 +521,6 @@ class YiiBase
 	 */
 	public static function t($message, $params = array(), $language = null)
 	{
-		Yii::$application->getI18N()->translate($message, $params, $language);
+		Yii::$app->getI18N()->translate($message, $params, $language);
 	}
 }
diff --git a/framework/base/Application.php b/framework/base/Application.php
index e4c1333..9277e70 100644
--- a/framework/base/Application.php
+++ b/framework/base/Application.php
@@ -105,7 +105,7 @@ class Application extends Module
 	 */
 	public function __construct($id, $basePath, $config = array())
 	{
-		Yii::$application = $this;
+		Yii::$app = $this;
 		$this->id = $id;
 		$this->setBasePath($basePath);
 
@@ -342,7 +342,7 @@ class Application extends Module
 	 */
 	public function registerDefaultAliases()
 	{
-		Yii::$aliases['@application'] = $this->getBasePath();
+		Yii::$aliases['@app'] = $this->getBasePath();
 		Yii::$aliases['@entry'] = dirname($_SERVER['SCRIPT_FILENAME']);
 		Yii::$aliases['@www'] = '';
 	}
diff --git a/framework/base/Controller.php b/framework/base/Controller.php
index 58deda2..ca3b39b 100644
--- a/framework/base/Controller.php
+++ b/framework/base/Controller.php
@@ -72,9 +72,9 @@ class Controller extends Component
 	 *
 	 * ~~~
 	 * return array(
-	 *     'action1' => '@application/components/Action1',
+	 *     'action1' => '@app/components/Action1',
 	 *     'action2' => array(
-	 *         'class' => '@application/components/Action2',
+	 *         'class' => '@app/components/Action2',
 	 *         'property1' => 'value1',
 	 *         'property2' => 'value2',
 	 *     ),
@@ -139,7 +139,7 @@ class Controller extends Component
 		} elseif ($pos > 0) {
 			return $this->module->runAction($route, $params);
 		} else {
-			return \Yii::$application->runAction(ltrim($route, '/'), $params);
+			return \Yii::$app->runAction(ltrim($route, '/'), $params);
 		}
 	}
 
diff --git a/framework/base/ErrorHandler.php b/framework/base/ErrorHandler.php
index 211bad6..9464a92 100644
--- a/framework/base/ErrorHandler.php
+++ b/framework/base/ErrorHandler.php
@@ -36,7 +36,7 @@ class ErrorHandler extends Component
 	public $discardExistingOutput = true;
 	/**
 	 * @var string the route (eg 'site/error') to the controller action that will be used to display external errors.
-	 * Inside the action, it can retrieve the error information by \Yii::$application->errorHandler->error.
+	 * Inside the action, it can retrieve the error information by \Yii::$app->errorHandler->error.
 	 * This property defaults to null, meaning ErrorHandler will handle the error display.
 	 */
 	public $errorAction;
@@ -71,14 +71,14 @@ class ErrorHandler extends Component
 	protected function render($exception)
 	{
 		if ($this->errorAction !== null) {
-			\Yii::$application->runAction($this->errorAction);
-		} elseif (\Yii::$application instanceof \yii\web\Application) {
+			\Yii::$app->runAction($this->errorAction);
+		} elseif (\Yii::$app instanceof \yii\web\Application) {
 			if (!headers_sent()) {
 				$errorCode = $exception instanceof HttpException ? $exception->statusCode : 500;
 				header("HTTP/1.0 $errorCode " . get_class($exception));
 			}
 			if (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] === 'XMLHttpRequest') {
-				\Yii::$application->renderException($exception);
+				\Yii::$app->renderException($exception);
 			} else {
 				$view = new View($this);
 				if (!YII_DEBUG || $exception instanceof UserException) {
@@ -91,7 +91,7 @@ class ErrorHandler extends Component
 				));
 			}
 		} else {
-			\Yii::$application->renderException($exception);
+			\Yii::$app->renderException($exception);
 		}
 	}
 
@@ -239,7 +239,7 @@ class ErrorHandler extends Component
 
 	public function htmlEncode($text)
 	{
-		return htmlspecialchars($text, ENT_QUOTES, \Yii::$application->charset);
+		return htmlspecialchars($text, ENT_QUOTES, \Yii::$app->charset);
 	}
 
 	public function clearOutput()
diff --git a/framework/base/Module.php b/framework/base/Module.php
index dcb468c..3217471 100644
--- a/framework/base/Module.php
+++ b/framework/base/Module.php
@@ -73,9 +73,9 @@ abstract class Module extends Component
 	 *
 	 * ~~~
 	 * array(
-	 *   'account' => '@application/controllers/UserController',
+	 *   'account' => '@app/controllers/UserController',
 	 *   'article' => array(
-	 *      'class' => '@application/controllers/PostController',
+	 *      'class' => '@app/controllers/PostController',
 	 *      'pageTitle' => 'something new',
 	 *   ),
 	 * )
@@ -311,7 +311,7 @@ abstract class Module extends Component
 	 *
 	 * ~~~
 	 * array(
-	 *	'@models' => '@application/models', // an existing alias
+	 *	'@models' => '@app/models', // an existing alias
 	 *	'@backend' => __DIR__ . '/../backend',  // a directory
 	 * )
 	 * ~~~
@@ -563,10 +563,10 @@ abstract class Module extends Component
 		if (is_array($result)) {
 			/** @var $controller Controller */
 			list($controller, $actionID) = $result;
-			$oldController = Yii::$application->controller;
-			Yii::$application->controller = $controller;
+			$oldController = Yii::$app->controller;
+			Yii::$app->controller = $controller;
 			$status = $controller->runAction($actionID, $params);
-			Yii::$application->controller = $oldController;
+			Yii::$app->controller = $oldController;
 			return $status;
 		} else {
 			throw new InvalidRouteException('Unable to resolve the request: ' . trim($this->getUniqueId() . '/' . $route, '/'));
diff --git a/framework/base/SecurityManager.php b/framework/base/SecurityManager.php
index a3fb654..18ccb03 100644
--- a/framework/base/SecurityManager.php
+++ b/framework/base/SecurityManager.php
@@ -59,12 +59,12 @@ class SecurityManager extends Component
 		if ($this->_validationKey !== null) {
 			return $this->_validationKey;
 		} else {
-			if (($key = \Yii::$application->getGlobalState(self::STATE_VALIDATION_KEY)) !== null) {
+			if (($key = \Yii::$app->getGlobalState(self::STATE_VALIDATION_KEY)) !== null) {
 				$this->setValidationKey($key);
 			} else {
 				$key = $this->generateRandomKey();
 				$this->setValidationKey($key);
-				\Yii::$application->setGlobalState(self::STATE_VALIDATION_KEY, $key);
+				\Yii::$app->setGlobalState(self::STATE_VALIDATION_KEY, $key);
 			}
 			return $this->_validationKey;
 		}
@@ -92,12 +92,12 @@ class SecurityManager extends Component
 		if ($this->_encryptionKey !== null) {
 			return $this->_encryptionKey;
 		} else {
-			if (($key = \Yii::$application->getGlobalState(self::STATE_ENCRYPTION_KEY)) !== null) {
+			if (($key = \Yii::$app->getGlobalState(self::STATE_ENCRYPTION_KEY)) !== null) {
 				$this->setEncryptionKey($key);
 			} else {
 				$key = $this->generateRandomKey();
 				$this->setEncryptionKey($key);
-				\Yii::$application->setGlobalState(self::STATE_ENCRYPTION_KEY, $key);
+				\Yii::$app->setGlobalState(self::STATE_ENCRYPTION_KEY, $key);
 			}
 			return $this->_encryptionKey;
 		}
diff --git a/framework/base/Theme.php b/framework/base/Theme.php
index 03f8f55..52d5245 100644
--- a/framework/base/Theme.php
+++ b/framework/base/Theme.php
@@ -58,7 +58,7 @@ class Theme extends Component
 		if (empty($this->pathMap)) {
 			if ($this->basePath !== null) {
 				$this->basePath = FileHelper::ensureDirectory($this->basePath);
-				$this->pathMap = array(Yii::$application->getBasePath() => $this->basePath);
+				$this->pathMap = array(Yii::$app->getBasePath() => $this->basePath);
 			} else {
 				throw new InvalidConfigException("Theme::basePath must be set.");
 			}
diff --git a/framework/base/UrlManager.php b/framework/base/UrlManager.php
index db6b598..e17685d 100644
--- a/framework/base/UrlManager.php
+++ b/framework/base/UrlManager.php
@@ -112,7 +112,7 @@ use \yii\base\Component;
  * </ul>
  *
  * UrlManager is a default application component that may be accessed via
- * {@link \Yii::$application->urlManager}.
+ * {@link \Yii::$app->urlManager}.
  *
  * @property string $baseUrl The base URL of the application (the part after host name and before query string).
  * If {@link showScriptName} is true, it will include the script name part.
@@ -214,7 +214,7 @@ class UrlManager extends Component
 	{
 		if(empty($this->rules) || $this->getUrlFormat()===self::GET_FORMAT)
 			return;
-		if($this->cacheID!==false && ($cache=\Yii::$application->getComponent($this->cacheID))!==null)
+		if($this->cacheID!==false && ($cache=\Yii::$app->getComponent($this->cacheID))!==null)
 		{
 			$hash=md5(serialize($this->rules));
 			if(($data=$cache->get(self::CACHE_KEY))!==false && isset($data[1]) && $data[1]===$hash)
@@ -464,9 +464,9 @@ class UrlManager extends Component
 		else
 		{
 			if($this->showScriptName)
-				$this->_baseUrl=\Yii::$application->getRequest()->getScriptUrl();
+				$this->_baseUrl=\Yii::$app->getRequest()->getScriptUrl();
 			else
-				$this->_baseUrl=\Yii::$application->getRequest()->getBaseUrl();
+				$this->_baseUrl=\Yii::$app->getRequest()->getBaseUrl();
 			return $this->_baseUrl;
 		}
 	}
@@ -755,7 +755,7 @@ class CUrlRule extends CBaseUrlRule
 
 		if($this->hasHostInfo)
 		{
-			$hostInfo=\Yii::$application->getRequest()->getHostInfo();
+			$hostInfo=\Yii::$app->getRequest()->getHostInfo();
 			if(stripos($url,$hostInfo)===0)
 				$url=substr($url,strlen($hostInfo));
 		}
diff --git a/framework/base/View.php b/framework/base/View.php
index 410e3c5..9caa4ef 100644
--- a/framework/base/View.php
+++ b/framework/base/View.php
@@ -148,7 +148,7 @@ class View extends Component
 	 */
 	public function renderFile($file, $params = array())
 	{
-		$renderer = Yii::$application->getViewRenderer();
+		$renderer = Yii::$app->getViewRenderer();
 		if ($renderer !== null) {
 			return $renderer->render($this, $file, $params);
 		} else {
@@ -344,7 +344,7 @@ class View extends Component
 	 *
 	 * A view name can be specified in one of the following formats:
 	 *
-	 * - path alias (e.g. "@application/views/site/index");
+	 * - path alias (e.g. "@app/views/site/index");
 	 * - absolute path within application (e.g. "//site/index"): the view name starts with double slashes.
 	 *   The actual view file will be looked for under the [[Application::viewPath|view path]] of the application.
 	 * - absolute path within module (e.g. "/site/index"): the view name starts with a single slash.
@@ -374,7 +374,7 @@ class View extends Component
 			$view .= '.php';
 		}
 		if (strncmp($view, '@', 1) === 0) {
-			// e.g. "@application/views/common"
+			// e.g. "@app/views/common"
 			if (($file = Yii::getAlias($view)) === false) {
 				throw new InvalidConfigException("Invalid path alias: $view");
 			}
@@ -386,18 +386,18 @@ class View extends Component
 				$class = new \ReflectionClass($this->owner);
 				$file = dirname($class->getFileName()) . DIRECTORY_SEPARATOR . 'views' . DIRECTORY_SEPARATOR . $view;
 			} else {
-				$file = Yii::$application->getViewPath() . DIRECTORY_SEPARATOR . $view;
+				$file = Yii::$app->getViewPath() . DIRECTORY_SEPARATOR . $view;
 			}
-		} elseif (strncmp($view, '//', 2) !== 0 && Yii::$application->controller !== null) {
+		} elseif (strncmp($view, '//', 2) !== 0 && Yii::$app->controller !== null) {
 			// e.g. "/site/index"
-			$file = Yii::$application->controller->module->getViewPath() . DIRECTORY_SEPARATOR . ltrim($view, '/');
+			$file = Yii::$app->controller->module->getViewPath() . DIRECTORY_SEPARATOR . ltrim($view, '/');
 		} else {
 			// e.g. "//layouts/main"
-			$file = Yii::$application->getViewPath() . DIRECTORY_SEPARATOR . ltrim($view, '/');
+			$file = Yii::$app->getViewPath() . DIRECTORY_SEPARATOR . ltrim($view, '/');
 		}
 
 		if (is_file($file)) {
-			if ($this->enableTheme && ($theme = Yii::$application->getTheme()) !== null) {
+			if ($this->enableTheme && ($theme = Yii::$app->getTheme()) !== null) {
 				$file = $theme->apply($file);
 			}
 			return $this->enableI18N ? FileHelper::localize($file, $this->language, $this->sourceLanguage) : $file;
@@ -423,7 +423,7 @@ class View extends Component
 	 *
 	 * Like view names, a layout name can take several formats:
 	 *
-	 * - path alias (e.g. "@application/views/layouts/main");
+	 * - path alias (e.g. "@app/views/layouts/main");
 	 * - absolute path (e.g. "/main"): the layout name starts with a slash. The actual layout file will be
 	 *   looked for under the [[Application::layoutPath|layout path]] of the application;
 	 * - relative path (e.g. "main"): the actual layout layout file will be looked for under the
@@ -444,10 +444,10 @@ class View extends Component
 	{
 		/** @var $module Module */
 		if (is_string($this->layout)) {
-			if (Yii::$application->controller) {
-				$module = Yii::$application->controller->module;
+			if (Yii::$app->controller) {
+				$module = Yii::$app->controller->module;
 			} else {
-				$module = Yii::$application;
+				$module = Yii::$app;
 			}
 			$view = $this->layout;
 		} elseif ($this->owner instanceof Controller) {
@@ -477,13 +477,13 @@ class View extends Component
 				throw new InvalidConfigException("Invalid path alias: $view");
 			}
 		} elseif (strncmp($view, '/', 1) === 0) {
-			$file = Yii::$application->getLayoutPath() . DIRECTORY_SEPARATOR . $view;
+			$file = Yii::$app->getLayoutPath() . DIRECTORY_SEPARATOR . $view;
 		} else {
 			$file = $module->getLayoutPath() . DIRECTORY_SEPARATOR . $view;
 		}
 
 		if (is_file($file)) {
-			if ($this->enableTheme && ($theme = Yii::$application->getTheme()) !== null) {
+			if ($this->enableTheme && ($theme = Yii::$app->getTheme()) !== null) {
 				$file = $theme->apply($file);
 			}
 			return $this->enableI18N ? FileHelper::localize($file, $this->language, $this->sourceLanguage) : $file;
diff --git a/framework/base/Widget.php b/framework/base/Widget.php
index bdec634..b494387 100644
--- a/framework/base/Widget.php
+++ b/framework/base/Widget.php
@@ -80,7 +80,7 @@ class Widget extends Component
 	 * To determine which view file should be rendered, the method calls [[findViewFile()]] which
 	 * will search in the directories as specified by [[basePath]].
 	 *
-	 * View name can be a path alias representing an absolute file path (e.g. `@application/views/layout/index`),
+	 * View name can be a path alias representing an absolute file path (e.g. `@app/views/layout/index`),
 	 * or a path relative to [[basePath]]. The file suffix is optional and defaults to `.php` if not given
 	 * in the view name.
 	 *
diff --git a/framework/caching/DbCache.php b/framework/caching/DbCache.php
index 4b84bfd..75f13b0 100644
--- a/framework/caching/DbCache.php
+++ b/framework/caching/DbCache.php
@@ -74,7 +74,7 @@ class DbCache extends Cache
 	public function getDb()
 	{
 		if ($this->_db === null) {
-			$db = \Yii::$application->getComponent($this->connectionID);
+			$db = \Yii::$app->getComponent($this->connectionID);
 			if ($db instanceof Connection) {
 				$this->_db = $db;
 			} else {
diff --git a/framework/caching/DbDependency.php b/framework/caching/DbDependency.php
index 7ffdb4e..e4cb547 100644
--- a/framework/caching/DbDependency.php
+++ b/framework/caching/DbDependency.php
@@ -91,7 +91,7 @@ class DbDependency extends Dependency
 	public function getDb()
 	{
 		if ($this->_db === null) {
-			$db = \Yii::$application->getComponent($this->connectionID);
+			$db = \Yii::$app->getComponent($this->connectionID);
 			if ($db instanceof Connection) {
 				$this->_db = $db;
 			} else {
diff --git a/framework/caching/DummyCache.php b/framework/caching/DummyCache.php
index f6e8a44..1f7a0c5 100644
--- a/framework/caching/DummyCache.php
+++ b/framework/caching/DummyCache.php
@@ -13,7 +13,7 @@ namespace yii\caching;
  * DummyCache is a placeholder cache component.
  *
  * DummyCache does not cache anything. It is provided so that one can always configure
- * a 'cache' application component and save the check of existence of `\Yii::$application->cache`.
+ * a 'cache' application component and save the check of existence of `\Yii::$app->cache`.
  * By replacing DummyCache with some other cache component, one can quickly switch from
  * non-caching mode to caching mode.
  *
diff --git a/framework/caching/FileCache.php b/framework/caching/FileCache.php
index f97861f..bf46fb6 100644
--- a/framework/caching/FileCache.php
+++ b/framework/caching/FileCache.php
@@ -28,7 +28,7 @@ class FileCache extends Cache
 	/**
 	 * @var string the directory to store cache files. You may use path alias here.
 	 */
-	public $cachePath = '@application/runtime/cache';
+	public $cachePath = '@app/runtime/cache';
 	/**
 	 * @var string cache file suffix. Defaults to '.bin'.
 	 */
diff --git a/framework/console/controllers/HelpController.php b/framework/console/controllers/HelpController.php
index 4a37f3d..5ad3bbc 100644
--- a/framework/console/controllers/HelpController.php
+++ b/framework/console/controllers/HelpController.php
@@ -55,7 +55,7 @@ class HelpController extends Controller
 	public function actionIndex($command = null)
 	{
 		if ($command !== null) {
-			$result = Yii::$application->createController($command);
+			$result = Yii::$app->createController($command);
 			if ($result === false) {
 				throw new Exception(Yii::t('yii|No help for unknown command "{command}".', array(
 					'{command}' => $command,
@@ -81,7 +81,7 @@ class HelpController extends Controller
 	 */
 	public function getCommands()
 	{
-		$commands = $this->getModuleCommands(Yii::$application);
+		$commands = $this->getModuleCommands(Yii::$app);
 		sort($commands);
 		return array_unique($commands);
 	}
diff --git a/framework/console/controllers/MigrateController.php b/framework/console/controllers/MigrateController.php
index 62e7d40..0f05d61 100644
--- a/framework/console/controllers/MigrateController.php
+++ b/framework/console/controllers/MigrateController.php
@@ -70,7 +70,7 @@ class MigrateController extends Controller
 	 * @var string the directory storing the migration classes. This can be either
 	 * a path alias or a directory.
 	 */
-	public $migrationPath = '@application/migrations';
+	public $migrationPath = '@app/migrations';
 	/**
 	 * @var string the name of the table for keeping applied migration information.
 	 */
@@ -82,7 +82,7 @@ class MigrateController extends Controller
 	public $connectionID = 'db';
 	/**
 	 * @var string the template file for generating new migrations.
-	 * This can be either a path alias (e.g. "@application/migrations/template.php")
+	 * This can be either a path alias (e.g. "@app/migrations/template.php")
 	 * or a file path.
 	 */
 	public $templateFile = '@yii/views/migration.php';
@@ -121,7 +121,7 @@ class MigrateController extends Controller
 			}
 			$this->migrationPath = $path;
 
-			$this->db = Yii::$application->getComponent($this->connectionID);
+			$this->db = Yii::$app->getComponent($this->connectionID);
 			if (!$this->db instanceof Connection) {
 				throw new Exception("Invalid DB connection \"{$this->connectionID}\".");
 			}
@@ -150,7 +150,7 @@ class MigrateController extends Controller
 	{
 		if (($migrations = $this->getNewMigrations()) === array()) {
 			echo "No new migration found. Your system is up-to-date.\n";
-			Yii::$application->end();
+			Yii::$app->end();
 		}
 
 		$total = count($migrations);
@@ -576,7 +576,7 @@ class MigrateController extends Controller
 		if ($this->db !== null) {
 			return $this->db;
 		} else {
-			$this->db = Yii::$application->getComponent($this->connectionID);
+			$this->db = Yii::$app->getComponent($this->connectionID);
 			if ($this->db instanceof Connection) {
 				return $this->db;
 			} else {
diff --git a/framework/db/ActiveRecord.php b/framework/db/ActiveRecord.php
index c6d3d81..0b2451f 100644
--- a/framework/db/ActiveRecord.php
+++ b/framework/db/ActiveRecord.php
@@ -96,7 +96,7 @@ class ActiveRecord extends Model
 	 */
 	public static function getDb()
 	{
-		return \Yii::$application->getDb();
+		return \Yii::$app->getDb();
 	}
 
 	/**
diff --git a/framework/db/Command.php b/framework/db/Command.php
index f893c8c..bb68f33 100644
--- a/framework/db/Command.php
+++ b/framework/db/Command.php
@@ -387,7 +387,7 @@ class Command extends \yii\base\Component
 
 		/** @var $cache \yii\caching\Cache */
 		if ($db->enableQueryCache && $method !== '') {
-			$cache = \Yii::$application->getComponent($db->queryCacheID);
+			$cache = \Yii::$app->getComponent($db->queryCacheID);
 		}
 
 		if (isset($cache)) {
diff --git a/framework/db/Migration.php b/framework/db/Migration.php
index 6dbaa78..c12da29 100644
--- a/framework/db/Migration.php
+++ b/framework/db/Migration.php
@@ -51,7 +51,7 @@ class Migration extends \yii\base\Component
 	{
 		parent::init();
 		if ($this->db === null) {
-			$this->db = \Yii::$application->getComponent('db');
+			$this->db = \Yii::$app->getComponent('db');
 		}
 	}
 
diff --git a/framework/db/Query.php b/framework/db/Query.php
index 10bba08..ffc6206 100644
--- a/framework/db/Query.php
+++ b/framework/db/Query.php
@@ -117,7 +117,7 @@ class Query extends \yii\base\Component
 	public function createCommand($db = null)
 	{
 		if ($db === null) {
-			$db = \Yii::$application->db;
+			$db = \Yii::$app->db;
 		}
 		$sql = $db->getQueryBuilder()->build($this);
 		return $db->createCommand($sql, $this->params);
diff --git a/framework/db/Schema.php b/framework/db/Schema.php
index 7415bee..6306776 100644
--- a/framework/db/Schema.php
+++ b/framework/db/Schema.php
@@ -87,7 +87,7 @@ abstract class Schema extends \yii\base\Object
 		$realName = $this->getRealTableName($name);
 
 		/** @var $cache Cache */
-		if ($db->enableSchemaCache && ($cache = \Yii::$application->getComponent($db->schemaCacheID)) !== null && !in_array($name, $db->schemaCacheExclude, true)) {
+		if ($db->enableSchemaCache && ($cache = \Yii::$app->getComponent($db->schemaCacheID)) !== null && !in_array($name, $db->schemaCacheExclude, true)) {
 			$key = $this->getCacheKey($cache, $name);
 			if ($refresh || ($table = $cache->get($key)) === false) {
 				$table = $this->loadTableSchema($realName);
@@ -171,7 +171,7 @@ abstract class Schema extends \yii\base\Object
 	public function refresh()
 	{
 		/** @var $cache \yii\caching\Cache */
-		if ($this->db->enableSchemaCache && ($cache = \Yii::$application->getComponent($this->db->schemaCacheID)) !== null) {
+		if ($this->db->enableSchemaCache && ($cache = \Yii::$app->getComponent($this->db->schemaCacheID)) !== null) {
 			foreach ($this->_tables as $name => $table) {
 				$cache->delete($this->getCacheKey($cache, $name));
 			}
diff --git a/framework/i18n/I18N.php b/framework/i18n/I18N.php
index fe09a84..42b7e07 100644
--- a/framework/i18n/I18N.php
+++ b/framework/i18n/I18N.php
@@ -10,10 +10,10 @@ class I18N extends Component
 	public function translate($message, $params = array(), $language = null)
 	{
 		if ($language === null) {
-			$language = Yii::$application->language;
+			$language = Yii::$app->language;
 		}
 
-		if (preg_match('/^([\w\-\.]+)\|(.*)/', $message, $matches)) {
+		if (strpos($message, '|') !== false && preg_match('/^([\w\-\.]+)\|(.*)/', $message, $matches)) {
 			$category = $matches[1];
 			$message = $matches[2];
 		} else {
diff --git a/framework/i18n/MessageSource.php b/framework/i18n/MessageSource.php
index 4f6bf94..e1df935 100644
--- a/framework/i18n/MessageSource.php
+++ b/framework/i18n/MessageSource.php
@@ -49,7 +49,7 @@ class MessageSource extends Component
 	{
 		parent::init();
 		if ($this->sourceLanguage === null) {
-			$this->sourceLanguage = Yii::$application->sourceLanguage;
+			$this->sourceLanguage = Yii::$app->sourceLanguage;
 		}
 	}
 
diff --git a/framework/logging/DbTarget.php b/framework/logging/DbTarget.php
index 129e4d4..8f38eb8 100644
--- a/framework/logging/DbTarget.php
+++ b/framework/logging/DbTarget.php
@@ -69,7 +69,7 @@ class DbTarget extends Target
 	public function getDb()
 	{
 		if ($this->_db === null) {
-			$db = \Yii::$application->getComponent($this->connectionID);
+			$db = \Yii::$app->getComponent($this->connectionID);
 			if ($db instanceof Connection) {
 				$this->_db = $db;
 			} else {
diff --git a/framework/logging/FileTarget.php b/framework/logging/FileTarget.php
index 0eb897e..e2dd56b 100644
--- a/framework/logging/FileTarget.php
+++ b/framework/logging/FileTarget.php
@@ -48,7 +48,7 @@ class FileTarget extends Target
 	{
 		parent::init();
 		if ($this->logFile === null) {
-			$this->logFile = \Yii::$application->getRuntimePath() . DIRECTORY_SEPARATOR . 'application.log';
+			$this->logFile = \Yii::$app->getRuntimePath() . DIRECTORY_SEPARATOR . 'application.log';
 		} else {
 			$this->logFile = \Yii::getAlias($this->logFile);
 		}
diff --git a/framework/logging/ProfileTarget.php b/framework/logging/ProfileTarget.php
index 6030669..d80ec18 100644
--- a/framework/logging/ProfileTarget.php
+++ b/framework/logging/ProfileTarget.php
@@ -71,7 +71,7 @@ class CProfileLogRoute extends CWebLogRoute
 	 */
 	public function processLogs($logs)
 	{
-		$app = \Yii::$application;
+		$app = \Yii::$app;
 		if (!($app instanceof CWebApplication) || $app->getRequest()->getIsAjaxRequest())
 			return;
 
diff --git a/framework/logging/Router.php b/framework/logging/Router.php
index 2e6a8dd..1e1f16c 100644
--- a/framework/logging/Router.php
+++ b/framework/logging/Router.php
@@ -52,7 +52,7 @@ use yii\base\Application;
  * as follows:
  *
  * ~~~
- * Yii::$application->log->targets['file']->enabled = false;
+ * Yii::$app->log->targets['file']->enabled = false;
  * ~~~
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
diff --git a/framework/logging/Target.php b/framework/logging/Target.php
index c9e175a..a75a512 100644
--- a/framework/logging/Target.php
+++ b/framework/logging/Target.php
@@ -110,7 +110,7 @@ abstract class Target extends \yii\base\Component
 	protected function getContextMessage()
 	{
 		$context = array();
-		if ($this->logUser && ($user = \Yii::$application->getComponent('user', false)) !== null) {
+		if ($this->logUser && ($user = \Yii::$app->getComponent('user', false)) !== null) {
 			$context[] = 'User: ' . $user->getName() . ' (ID: ' . $user->getId() . ')';
 		}
 
diff --git a/framework/logging/WebTarget.php b/framework/logging/WebTarget.php
index 6ce8ea0..7198b3a 100644
--- a/framework/logging/WebTarget.php
+++ b/framework/logging/WebTarget.php
@@ -46,7 +46,7 @@ class CWebLogRoute extends CLogRoute
 	 */
 	protected function render($view, $data)
 	{
-		$app = \Yii::$application;
+		$app = \Yii::$app;
 		$isAjax = $app->getRequest()->getIsAjaxRequest();
 
 		if ($this->showInFireBug)
diff --git a/framework/util/FileHelper.php b/framework/util/FileHelper.php
index c65e4f0..6565c77 100644
--- a/framework/util/FileHelper.php
+++ b/framework/util/FileHelper.php
@@ -91,10 +91,10 @@ class FileHelper
 	public static function localize($file, $language = null, $sourceLanguage = null)
 	{
 		if ($language === null) {
-			$language = \Yii::$application->getLanguage();
+			$language = \Yii::$app->getLanguage();
 		}
 		if ($sourceLanguage === null) {
-			$sourceLanguage = \Yii::$application->sourceLanguage;
+			$sourceLanguage = \Yii::$app->sourceLanguage;
 		}
 		if ($language === $sourceLanguage) {
 			return $file;
diff --git a/framework/validators/CaptchaValidator.php b/framework/validators/CaptchaValidator.php
index 1b6c303..2303333 100644
--- a/framework/validators/CaptchaValidator.php
+++ b/framework/validators/CaptchaValidator.php
@@ -61,13 +61,13 @@ class CaptchaValidator extends Validator
 	public function getCaptchaAction()
 	{
 		if (strpos($this->captchaAction, '/') !== false) {  // contains controller or module
-			$ca = \Yii::$application->createController($this->captchaAction);
+			$ca = \Yii::$app->createController($this->captchaAction);
 			if ($ca !== null) {
 				list($controller, $actionID) = $ca;
 				$action = $controller->createAction($actionID);
 			}
 		} else {
-			$action = \Yii::$application->getController()->createAction($this->captchaAction);
+			$action = \Yii::$app->getController()->createAction($this->captchaAction);
 		}
 
 		if ($action === null) {
diff --git a/framework/validators/StringValidator.php b/framework/validators/StringValidator.php
index c57e183..b39abb8 100644
--- a/framework/validators/StringValidator.php
+++ b/framework/validators/StringValidator.php
@@ -82,7 +82,7 @@ class StringValidator extends Validator
 		}
 
 		if (function_exists('mb_strlen') && $this->encoding !== false) {
-			$length = mb_strlen($value, $this->encoding ? $this->encoding : \Yii::$application->charset);
+			$length = mb_strlen($value, $this->encoding ? $this->encoding : \Yii::$app->charset);
 		} else {
 			$length = strlen($value);
 		}
diff --git a/framework/web/AssetManager.php b/framework/web/AssetManager.php
index 1c5965a..0d3248b 100644
--- a/framework/web/AssetManager.php
+++ b/framework/web/AssetManager.php
@@ -97,7 +97,7 @@ class CAssetManager extends CApplicationComponent
 	{
 		if($this->_basePath===null)
 		{
-			$request=\Yii::$application->getRequest();
+			$request=\Yii::$app->getRequest();
 			$this->setBasePath(dirname($request->getScriptFile()).DIRECTORY_SEPARATOR.self::DEFAULT_BASEPATH);
 		}
 		return $this->_basePath;
@@ -125,7 +125,7 @@ class CAssetManager extends CApplicationComponent
 	{
 		if($this->_baseUrl===null)
 		{
-			$request=\Yii::$application->getRequest();
+			$request=\Yii::$app->getRequest();
 			$this->setBaseUrl($request->getBaseUrl().'/'.self::DEFAULT_BASEPATH);
 		}
 		return $this->_baseUrl;
diff --git a/framework/web/Controller.php b/framework/web/Controller.php
index 6c0bc28..22cb8e7 100644
--- a/framework/web/Controller.php
+++ b/framework/web/Controller.php
@@ -59,9 +59,9 @@ class Controller extends \yii\base\Controller
 		else {
 			$name = ucfirst(basename($this->id));
 			if($this->action!==null && strcasecmp($this->action->id,$this->defaultAction))
-				return $this->_pageTitle=\Yii::$application->name.' - '.ucfirst($this->action->id).' '.$name;
+				return $this->_pageTitle=\Yii::$app->name.' - '.ucfirst($this->action->id).' '.$name;
 			else
-				return $this->_pageTitle=\Yii::$application->name.' - '.$name;
+				return $this->_pageTitle=\Yii::$app->name.' - '.$name;
 		}
 	}
 
diff --git a/framework/web/Request.php b/framework/web/Request.php
index 68d6044..8337382 100644
--- a/framework/web/Request.php
+++ b/framework/web/Request.php
@@ -87,7 +87,7 @@ class Request extends \yii\base\Request
 		}
 
 		if ($this->enableCsrfValidation) {
-			\Yii::$application->on('beginRequest', array($this, 'validateCsrfToken'));
+			\Yii::$app->on('beginRequest', array($this, 'validateCsrfToken'));
 		}
 	}
 
diff --git a/framework/web/Sort.php b/framework/web/Sort.php
index 12e16a5..6b128e7 100644
--- a/framework/web/Sort.php
+++ b/framework/web/Sort.php
@@ -307,7 +307,7 @@ class CSort extends CComponent
 			$directions = array($attribute => $descending);
 		}
 
-		$url = $this->createUrl(\Yii::$application->getController(), $directions);
+		$url = $this->createUrl(\Yii::$app->getController(), $directions);
 
 		return $this->createLink($attribute, $label, $url, $htmlOptions);
 	}
diff --git a/framework/web/Theme.php b/framework/web/Theme.php
index 5dcd601..22fe608 100644
--- a/framework/web/Theme.php
+++ b/framework/web/Theme.php
@@ -126,7 +126,7 @@ class CTheme extends CComponent
 				$module=$module->getParentModule();
 			}
 			if($module===null)
-				$layoutName=\Yii::$application->layout;
+				$layoutName=\Yii::$app->layout;
 			else
 			{
 				$layoutName=$module->layout;