Introduce ClassNotFoundException for container

src/Container/GenericContainer.php

@@ -43,7 +43,7 @@ class GenericContainer implements ContainerInterface
             $className = $this->aliases[$className];
         }
         if (!isset($this->definitions[$className])) {
-            throw new Exception("Class $className not found in container");
+            throw new ClassNotFoundException($className);
         }
 
         $definition = $this->definitions[$className]['definition'];