diff --git a/framework/yii/YiiBase.php b/framework/yii/YiiBase.php
index a5a3833..c96a969 100644
--- a/framework/yii/YiiBase.php
+++ b/framework/yii/YiiBase.php
@@ -100,7 +100,6 @@ class YiiBase
 	 */
 	public static $objectConfig = array();
 
-	private static $_imported = array(); // alias => class name or directory
 
 	/**
 	 * @return string the version of Yii framework
@@ -111,40 +110,6 @@ class YiiBase
 	}
 
 	/**
-	 * Imports a class by its alias.
-	 *
-	 * This method is provided to support autoloading of non-namespaced classes.
-	 * Such a class can be specified in terms of an alias. For example, the alias `@old/code/Sample`
-	 * may represent the `Sample` class under the directory `@old/code` (a path alias).
-	 *
-	 * By importing a class, the class is put in an internal storage such that when
-	 * the class is used for the first time, the class autoloader will be able to
-	 * find the corresponding class file and include it. For this reason, this method
-	 * is much lighter than `include()`.
-	 *
-	 * You may import the same class multiple times. Only the first importing will count.
-	 *
-	 * @param string $alias the class to be imported. This may be either a class alias or a fully-qualified class name.
-	 * If the latter, it will be returned back without change.
-	 * @return string the actual class name that `$alias` refers to
-	 * @throws Exception if the alias is invalid
-	 */
-	public static function import($alias)
-	{
-		if (strncmp($alias, '@', 1)) {
-			return $alias;
-		} else {
-			$alias = static::getAlias($alias);
-			if (!isset(self::$_imported[$alias])) {
-				$className = basename($alias);
-				self::$_imported[$alias] = $className;
-				self::$classMap[$className] = $alias . '.php';
-			}
-			return self::$_imported[$alias];
-		}
-	}
-
-	/**
 	 * Imports a set of namespaces.
 	 *
 	 * By importing a namespace, the method will create an alias for the directory corresponding
@@ -431,10 +396,6 @@ class YiiBase
 			throw new InvalidConfigException('Object configuration must be an array containing a "class" element.');
 		}
 
-		if (!class_exists($class, false)) {
-			$class = static::import($class);
-		}
-
 		$class = ltrim($class, '\\');
 
 		if (isset(self::$objectConfig[$class])) {
diff --git a/framework/yii/validators/ExistValidator.php b/framework/yii/validators/ExistValidator.php
index 9c74890..8cbce5f 100644
--- a/framework/yii/validators/ExistValidator.php
+++ b/framework/yii/validators/ExistValidator.php
@@ -66,7 +66,7 @@ class ExistValidator extends Validator
 		}
 
 		/** @var $className \yii\db\ActiveRecord */
-		$className = $this->className === null ? get_class($object) : Yii::import($this->className);
+		$className = $this->className === null ? get_class($object) : $this->className;
 		$attributeName = $this->attributeName === null ? $attribute : $this->attributeName;
 		$query = $className::find();
 		$query->where(array($attributeName => $value));
diff --git a/framework/yii/validators/UniqueValidator.php b/framework/yii/validators/UniqueValidator.php
index b650693..c3876e8 100644
--- a/framework/yii/validators/UniqueValidator.php
+++ b/framework/yii/validators/UniqueValidator.php
@@ -61,7 +61,7 @@ class UniqueValidator extends Validator
 		}
 
 		/** @var $className \yii\db\ActiveRecord */
-		$className = $this->className === null ? get_class($object) : Yii::import($this->className);
+		$className = $this->className === null ? get_class($object) : $this->className;
 		$attributeName = $this->attributeName === null ? $attribute : $this->attributeName;
 
 		$table = $className::getTableSchema();
diff --git a/framework/yii/web/User.php b/framework/yii/web/User.php
index b1ca8c2..e02559b 100644
--- a/framework/yii/web/User.php
+++ b/framework/yii/web/User.php
@@ -140,7 +140,7 @@ class User extends Component
 				$this->_identity = null;
 			} else {
 				/** @var $class Identity */
-				$class = Yii::import($this->identityClass);
+				$class = $this->identityClass;
 				$this->_identity = $class::findIdentity($id);
 			}
 		}