diff --git a/core/lib/Drupal/Component/Archiver/ArchiveTar.php b/core/lib/Drupal/Component/Archiver/ArchiveTar.php
index 4a8d828..a0ffb53 100644
--- a/core/lib/Drupal/Component/Archiver/ArchiveTar.php
+++ b/core/lib/Drupal/Component/Archiver/ArchiveTar.php
@@ -42,8 +42,6 @@
 
 namespace Drupal\Component\Archiver;
 
-use Exception;
-
 //require_once 'PEAR.php';
 //
 //
@@ -636,7 +634,7 @@ class ArchiveTar // extends PEAR
     {
         // ----- To be completed
 //        $this->raiseError($p_message);
-        throw new Exception($p_message);
+        throw new \Exception($p_message);
     }
     // }}}
 
@@ -645,7 +643,7 @@ class ArchiveTar // extends PEAR
     {
         // ----- To be completed
 //        $this->raiseError($p_message);
-        throw new Exception($p_message);
+        throw new \Exception($p_message);
     }
     // }}}
 
diff --git a/core/lib/Drupal/Component/Archiver/ArchiverException.php b/core/lib/Drupal/Component/Archiver/ArchiverException.php
index 12af470..abf7325 100644
--- a/core/lib/Drupal/Component/Archiver/ArchiverException.php
+++ b/core/lib/Drupal/Component/Archiver/ArchiverException.php
@@ -7,10 +7,8 @@
 
 namespace Drupal\Component\Archiver;
 
-use Exception;
-
 /**
  * Defines an exception class for Drupal\Component\Archiver\ArchiverInterface.
  */
-class ArchiverException extends Exception {
+class ArchiverException extends \Exception {
 }
diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackend.php b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
index 9416548..69b1a49 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackend.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
@@ -7,8 +7,6 @@
 
 namespace Drupal\Core\Cache;
 
-use Exception;
-
 /**
  * Defines a default cache implementation.
  *
@@ -74,7 +72,7 @@ class DatabaseBackend implements CacheBackendInterface {
       $cids = array_diff($cids, array_keys($cache));
       return $cache;
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       // If the database is never going to be available, cache requests should
       // return FALSE in order to allow exception handling to occur.
       return array();
@@ -152,7 +150,7 @@ class DatabaseBackend implements CacheBackendInterface {
         ->fields($fields)
         ->execute();
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       // The database may not be available, so we'll ignore cache_set requests.
     }
   }
diff --git a/core/lib/Drupal/Core/Cache/InstallBackend.php b/core/lib/Drupal/Core/Cache/InstallBackend.php
index b527d56..cf84c64 100644
--- a/core/lib/Drupal/Core/Cache/InstallBackend.php
+++ b/core/lib/Drupal/Core/Cache/InstallBackend.php
@@ -7,8 +7,6 @@
 
 namespace Drupal\Core\Cache;
 
-use Exception;
-
 /**
  * Defines a stub cache implementation to be used during installation.
  *
@@ -61,7 +59,7 @@ class InstallBackend extends DatabaseBackend {
         parent::delete($cid);
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
   }
 
   /**
@@ -73,7 +71,7 @@ class InstallBackend extends DatabaseBackend {
         parent::deleteMultiple($cids);
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
   }
 
   /**
@@ -85,7 +83,7 @@ class InstallBackend extends DatabaseBackend {
         parent::deletePrefix($prefix);
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
   }
 
   /**
@@ -97,7 +95,7 @@ class InstallBackend extends DatabaseBackend {
         parent::invalidateTags($tags);
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
   }
 
   /**
@@ -109,7 +107,7 @@ class InstallBackend extends DatabaseBackend {
         parent::flush();
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
   }
 
   /**
@@ -121,7 +119,7 @@ class InstallBackend extends DatabaseBackend {
         parent::expire();
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
   }
 
   /**
@@ -133,7 +131,7 @@ class InstallBackend extends DatabaseBackend {
         parent::garbageCollection();
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
   }
 
   /**
@@ -145,7 +143,7 @@ class InstallBackend extends DatabaseBackend {
         return parent::isEmpty();
       }
     }
-    catch (Exception $e) {}
+    catch (\Exception $e) {}
     return TRUE;
   }
 }
diff --git a/core/lib/Drupal/Core/Config/DatabaseStorage.php b/core/lib/Drupal/Core/Config/DatabaseStorage.php
index c736245..c7db0ec 100644
--- a/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ b/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -3,7 +3,6 @@
 namespace Drupal\Core\Config;
 
 use Drupal\Core\Config\StorageBase;
-use Exception;
 
 /**
  * Represents an SQL-based configuration storage object.
@@ -25,7 +24,7 @@ class DatabaseStorage extends StorageBase {
         $data = $this->decode($raw);
       }
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
     }
     return $data;
   }
diff --git a/core/lib/Drupal/Core/Database/Connection.php b/core/lib/Drupal/Core/Database/Connection.php
index 94a23fb..2eb95ea 100644
--- a/core/lib/Drupal/Core/Database/Connection.php
+++ b/core/lib/Drupal/Core/Database/Connection.php
@@ -10,9 +10,6 @@ namespace Drupal\Core\Database;
 use Drupal\Core\Database\TransactionNoActiveException;
 use Drupal\Core\Database\TransactionOutOfOrderException;
 
-use PDO;
-use PDOException;
-
 /**
  * Base Database API class.
  *
@@ -23,7 +20,7 @@ use PDOException;
  *
  * @see http://php.net/manual/book.pdo.php
  */
-abstract class Connection extends PDO {
+abstract class Connection extends \PDO {
 
   /**
    * The database target this connection is for.
@@ -140,14 +137,14 @@ abstract class Connection extends PDO {
     $this->setPrefix(isset($this->connectionOptions['prefix']) ? $this->connectionOptions['prefix'] : '');
 
     // Because the other methods don't seem to work right.
-    $driver_options[PDO::ATTR_ERRMODE] = PDO::ERRMODE_EXCEPTION;
+    $driver_options[\PDO::ATTR_ERRMODE] = \PDO::ERRMODE_EXCEPTION;
 
     // Call PDO::__construct and PDO::setAttribute.
     parent::__construct($dsn, $username, $password, $driver_options);
 
     // Set a specific PDOStatement class if the driver requires that.
     if (!empty($this->statementClass)) {
-      $this->setAttribute(PDO::ATTR_STATEMENT_CLASS, array($this->statementClass, array($this)));
+      $this->setAttribute(\PDO::ATTR_STATEMENT_CLASS, array($this->statementClass, array($this)));
     }
   }
 
@@ -199,7 +196,7 @@ abstract class Connection extends PDO {
   protected function defaultOptions() {
     return array(
       'target' => 'default',
-      'fetch' => PDO::FETCH_OBJ,
+      'fetch' => \PDO::FETCH_OBJ,
       'return' => Database::RETURN_STATEMENT,
       'throw_exception' => TRUE,
     );
@@ -519,10 +516,10 @@ abstract class Connection extends PDO {
         case Database::RETURN_NULL:
           return;
         default:
-          throw new PDOException('Invalid return directive: ' . $options['return']);
+          throw new \PDOException('Invalid return directive: ' . $options['return']);
       }
     }
-    catch (PDOException $e) {
+    catch (\PDOException $e) {
       if ($options['throw_exception']) {
         // Wrap the exception in another exception, because PHP does not allow
         // overriding Exception::getMessage(). Its message is the extra database
@@ -1041,7 +1038,7 @@ abstract class Connection extends PDO {
    * Returns the version of the database server.
    */
   public function version() {
-    return $this->getAttribute(PDO::ATTR_SERVER_VERSION);
+    return $this->getAttribute(\PDO::ATTR_SERVER_VERSION);
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Database/DatabaseExceptionWrapper.php b/core/lib/Drupal/Core/Database/DatabaseExceptionWrapper.php
index b212478..f9527d4 100644
--- a/core/lib/Drupal/Core/Database/DatabaseExceptionWrapper.php
+++ b/core/lib/Drupal/Core/Database/DatabaseExceptionWrapper.php
@@ -7,13 +7,11 @@
 
 namespace Drupal\Core\Database;
 
-use RuntimeException;
-
 /**
  * This wrapper class serves only to provide additional debug information.
  *
  * This class will always wrap a PDOException.
  */
-class DatabaseExceptionWrapper extends RuntimeException implements DatabaseException {
+class DatabaseExceptionWrapper extends \RuntimeException implements DatabaseException {
 
 }
diff --git a/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php b/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
index fbbff42..629fd68 100644
--- a/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
@@ -14,8 +14,6 @@ use Drupal\Core\Database\TransactionCommitFailedException;
 use Drupal\Core\Database\DatabaseException;
 use Drupal\Core\Database\Connection as DatabaseConnection;
 
-use PDO;
-
 /**
  * @addtogroup database
  * @{
@@ -54,9 +52,9 @@ class Connection extends DatabaseConnection {
     );
     $connection_options['pdo'] += array(
       // So we don't have to mess around with cursors and unbuffered queries by default.
-      PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,
+      \PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,
       // Because MySQL's prepared statements skip the query cache, because it's dumb.
-      PDO::ATTR_EMULATE_PREPARES => TRUE,
+      \PDO::ATTR_EMULATE_PREPARES => TRUE,
     );
 
     parent::__construct($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']);
@@ -173,7 +171,7 @@ class Connection extends DatabaseConnection {
       // If there are no more layers left then we should commit.
       unset($this->transactionLayers[$name]);
       if (empty($this->transactionLayers)) {
-        if (!PDO::commit()) {
+        if (!\PDO::commit()) {
           throw new TransactionCommitFailedException();
         }
       }
@@ -196,7 +194,7 @@ class Connection extends DatabaseConnection {
             $this->transactionLayers = array();
             // We also have to explain to PDO that the transaction stack has
             // been cleaned-up.
-            PDO::commit();
+            \PDO::commit();
           }
           else {
             throw $e;
diff --git a/core/lib/Drupal/Core/Database/Driver/mysql/Schema.php b/core/lib/Drupal/Core/Database/Driver/mysql/Schema.php
index 37efb97..b9e8b6d 100644
--- a/core/lib/Drupal/Core/Database/Driver/mysql/Schema.php
+++ b/core/lib/Drupal/Core/Database/Driver/mysql/Schema.php
@@ -13,8 +13,6 @@ use Drupal\Core\Database\SchemaObjectExistsException;
 use Drupal\Core\Database\SchemaObjectDoesNotExistException;
 use Drupal\Core\Database\Schema as DatabaseSchema;
 
-use Exception;
-
 /**
  * @addtogroup schemaapi
  * @{
@@ -516,7 +514,7 @@ class Schema extends DatabaseSchema {
       $this->connection->queryRange("SELECT 1 FROM {" . $table . "}", 0, 1);
       return TRUE;
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       return FALSE;
     }
   }
@@ -533,7 +531,7 @@ class Schema extends DatabaseSchema {
       $this->connection->queryRange("SELECT $column FROM {" . $table . "}", 0, 1);
       return TRUE;
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       return FALSE;
     }
   }
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
index b3f6d64..48db03b 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
@@ -11,9 +11,6 @@ use Drupal\Core\Database\Database;
 use Drupal\Core\Database\Connection as DatabaseConnection;
 use Drupal\Core\Database\StatementInterface;
 
-use PDO;
-use PDOException;
-
 /**
  * @addtogroup database
  * @{
@@ -68,9 +65,9 @@ class Connection extends DatabaseConnection {
       // prepared queries are not re-used, it should be faster to emulate
       // the preparation than to actually ready statements for re-use. If in
       // doubt, reset to FALSE and measure performance.
-      PDO::ATTR_EMULATE_PREPARES => TRUE,
+      \PDO::ATTR_EMULATE_PREPARES => TRUE,
       // Convert numeric values to strings when fetching.
-      PDO::ATTR_STRINGIFY_FETCHES => TRUE,
+      \PDO::ATTR_STRINGIFY_FETCHES => TRUE,
     );
     parent::__construct($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']);
 
@@ -119,10 +116,10 @@ class Connection extends DatabaseConnection {
         case Database::RETURN_NULL:
           return;
         default:
-          throw new PDOException('Invalid return directive: ' . $options['return']);
+          throw new \PDOException('Invalid return directive: ' . $options['return']);
       }
     }
-    catch (PDOException $e) {
+    catch (\PDOException $e) {
       if ($options['throw_exception']) {
         // Add additional debug information.
         if ($query instanceof StatementInterface) {
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Insert.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Insert.php
index dffa1fd..eb5a51d 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Insert.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Insert.php
@@ -10,8 +10,6 @@ namespace Drupal\Core\Database\Driver\pgsql;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Database\Query\Insert as QueryInsert;
 
-use PDO;
-
 /**
  * @ingroup database
  * @{
@@ -39,7 +37,7 @@ class Insert extends QueryInsert {
           fwrite($blobs[$blob_count], $insert_values[$idx]);
           rewind($blobs[$blob_count]);
 
-          $stmt->bindParam(':db_insert_placeholder_' . $max_placeholder++, $blobs[$blob_count], PDO::PARAM_LOB);
+          $stmt->bindParam(':db_insert_placeholder_' . $max_placeholder++, $blobs[$blob_count], \PDO::PARAM_LOB);
 
           // Pre-increment is faster in PHP than increment.
           ++$blob_count;
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
index 6dc40a2..7c50bf9 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
@@ -10,8 +10,6 @@ namespace Drupal\Core\Database\Driver\pgsql\Install;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Database\Install\Tasks as InstallTasks;
 
-use Exception;
-
 /**
  * PostgreSQL specific install functions
  */
@@ -60,7 +58,7 @@ class Tasks extends InstallTasks {
         $this->fail(st($text, $replacements));
       }
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(st('Drupal could not determine the encoding of the database was set to UTF-8'));
     }
   }
@@ -87,7 +85,7 @@ class Tasks extends InstallTasks {
         try {
           db_query($query);
         }
-        catch (Exception $e) {
+        catch (\Exception $e) {
           // Ignore possible errors when the user doesn't have the necessary
           // privileges to ALTER the database.
         }
@@ -175,7 +173,7 @@ class Tasks extends InstallTasks {
 
       $this->pass(st('PostgreSQL has initialized itself.'));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(st('Drupal could not be correctly setup with the existing database. Revise any errors.'));
     }
   }
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
index 6ce4a0a..d08e6c5 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
@@ -13,8 +13,6 @@ use Drupal\Core\Database\SchemaObjectExistsException;
 use Drupal\Core\Database\SchemaObjectDoesNotExistException;
 use Drupal\Core\Database\Schema as DatabaseSchema;
 
-use Exception;
-
 /**
  * @addtogroup schemaapi
  * @{
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Update.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Update.php
index de738bf..60dc15d 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Update.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Update.php
@@ -10,8 +10,6 @@ namespace Drupal\Core\Database\Driver\pgsql;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Database\Query\Update as QueryUpdate;
 
-use PDO;
-
 class Update extends QueryUpdate {
 
   public function execute() {
@@ -49,7 +47,7 @@ class Update extends QueryUpdate {
         $blobs[$blob_count] = fopen('php://memory', 'a');
         fwrite($blobs[$blob_count], $value);
         rewind($blobs[$blob_count]);
-        $stmt->bindParam($placeholder, $blobs[$blob_count], PDO::PARAM_LOB);
+        $stmt->bindParam($placeholder, $blobs[$blob_count], \PDO::PARAM_LOB);
         ++$blob_count;
       }
       else {
diff --git a/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php b/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
index 02a55a4..718f812 100644
--- a/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
@@ -14,9 +14,6 @@ use Drupal\Core\Database\TransactionCommitFailedException;
 use Drupal\Core\Database\Driver\sqlite\Statement;
 use Drupal\Core\Database\Connection as DatabaseConnection;
 
-use PDO;
-use Exception;
-
 /**
  * Specific SQLite implementation of DatabaseConnection.
  */
@@ -74,7 +71,7 @@ class Connection extends DatabaseConnection {
     );
     $connection_options['pdo'] += array(
       // Convert numeric values to strings when fetching.
-      PDO::ATTR_STRINGIFY_FETCHES => TRUE,
+      \PDO::ATTR_STRINGIFY_FETCHES => TRUE,
     );
     parent::__construct('sqlite:' . $connection_options['database'], '', '', $connection_options['pdo']);
 
@@ -140,7 +137,7 @@ class Connection extends DatabaseConnection {
             unlink($this->connectionOptions['database'] . '-' . $prefix);
           }
         }
-        catch (Exception $e) {
+        catch (\Exception $e) {
           // Ignore the exception and continue. There is nothing we can do here
           // to report the error or fail safe.
         }
@@ -331,7 +328,7 @@ class Connection extends DatabaseConnection {
       }
     }
     if ($this->supportsTransactions()) {
-      PDO::rollBack();
+      \PDO::rollBack();
     }
   }
 
@@ -346,7 +343,7 @@ class Connection extends DatabaseConnection {
       throw new TransactionNameNonUniqueException($name . " is already in use.");
     }
     if (!$this->inTransaction()) {
-      PDO::beginTransaction();
+      \PDO::beginTransaction();
     }
     $this->transactionLayers[$name] = $name;
   }
@@ -371,9 +368,9 @@ class Connection extends DatabaseConnection {
         // If there was any rollback() we should roll back whole transaction.
         if ($this->willRollback) {
           $this->willRollback = FALSE;
-          PDO::rollBack();
+          \PDO::rollBack();
         }
-        elseif (!PDO::commit()) {
+        elseif (!\PDO::commit()) {
           throw new TransactionCommitFailedException();
         }
       }
diff --git a/core/lib/Drupal/Core/Database/Driver/sqlite/Schema.php b/core/lib/Drupal/Core/Database/Driver/sqlite/Schema.php
index 823cd13..b28c5fe 100644
--- a/core/lib/Drupal/Core/Database/Driver/sqlite/Schema.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Schema.php
@@ -11,8 +11,6 @@ use Drupal\Core\Database\SchemaObjectExistsException;
 use Drupal\Core\Database\SchemaObjectDoesNotExistException;
 use Drupal\Core\Database\Schema as DatabaseSchema;
 
-use Exception;
-
 
 /**
  * @ingroup schemaapi
@@ -451,7 +449,7 @@ class Schema extends DatabaseSchema {
         }
       }
       else {
-        new Exception("Unable to parse the column type " . $row->type);
+        new \Exception("Unable to parse the column type " . $row->type);
       }
     }
     $indexes = array();
@@ -688,4 +686,4 @@ class Schema extends DatabaseSchema {
     ));
     return $result->fetchAllKeyed(0, 0);
   }
-}
\ No newline at end of file
+}
diff --git a/core/lib/Drupal/Core/Database/Driver/sqlite/Statement.php b/core/lib/Drupal/Core/Database/Driver/sqlite/Statement.php
index 531b6d0..0adc6c2 100644
--- a/core/lib/Drupal/Core/Database/Driver/sqlite/Statement.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Statement.php
@@ -10,9 +10,6 @@ namespace Drupal\Core\Database\Driver\sqlite;
 use Drupal\Core\Database\StatementPrefetch;
 use Drupal\Core\Database\StatementInterface;
 
-use Iterator;
-use PDOException;
-
 /**
  * Specific SQLite implementation of DatabaseConnection.
  *
@@ -21,7 +18,7 @@ use PDOException;
  *
  * @see DatabaseConnection_sqlite::PDOPrepare()
  */
-class Statement extends StatementPrefetch implements Iterator, StatementInterface {
+class Statement extends StatementPrefetch implements \Iterator, StatementInterface {
 
   /**
    * SQLite specific implementation of getStatement().
@@ -93,7 +90,7 @@ class Statement extends StatementPrefetch implements Iterator, StatementInterfac
     try {
       $return = parent::execute($args, $options);
     }
-    catch (PDOException $e) {
+    catch (\PDOException $e) {
       if (!empty($e->errorInfo[1]) && $e->errorInfo[1] === 17) {
         // The schema has changed. SQLite specifies that we must resend the query.
         $return = parent::execute($args, $options);
diff --git a/core/lib/Drupal/Core/Database/Install/Tasks.php b/core/lib/Drupal/Core/Database/Install/Tasks.php
index 5d34a62..f1370be 100644
--- a/core/lib/Drupal/Core/Database/Install/Tasks.php
+++ b/core/lib/Drupal/Core/Database/Install/Tasks.php
@@ -9,9 +9,6 @@ namespace Drupal\Core\Database\Install;
 
 use Drupal\Core\Database\Database;
 
-use PDO;
-use Exception;
-
 /**
  * Database installer structure.
  *
@@ -81,7 +78,7 @@ abstract class Tasks {
    * Ensure the PDO driver is supported by the version of PHP in use.
    */
   protected function hasPdoDriver() {
-    return in_array($this->pdoDriver, PDO::getAvailableDrivers());
+    return in_array($this->pdoDriver, \PDO::getAvailableDrivers());
   }
 
   /**
@@ -166,7 +163,7 @@ abstract class Tasks {
       Database::getConnection();
       $this->pass('Drupal can CONNECT to the database ok.');
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(st('Failed to connect to your database server. The server reports the following message: %error.<ul><li>Is the database server running?</li><li>Does the database exist, and have you entered the correct database name?</li><li>Have you entered the correct username and password?</li><li>Have you entered the correct database hostname?</li></ul>', array('%error' => $e->getMessage())));
       return FALSE;
     }
@@ -181,7 +178,7 @@ abstract class Tasks {
       db_query($query);
       $this->pass(st($pass));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(st($fail, array('%query' => $query, '%error' => $e->getMessage(), '%name' => $this->name())));
       return !$fatal;
     }
diff --git a/core/lib/Drupal/Core/Database/Query/Insert.php b/core/lib/Drupal/Core/Database/Query/Insert.php
index b3c4c0e..7862436 100644
--- a/core/lib/Drupal/Core/Database/Query/Insert.php
+++ b/core/lib/Drupal/Core/Database/Query/Insert.php
@@ -9,8 +9,6 @@ namespace Drupal\Core\Database\Query;
 
 use Drupal\Core\Database\Database;
 
-use Exception;
-
 /**
  * General class for an abstracted INSERT query.
  */
@@ -220,7 +218,7 @@ class Insert extends Query {
         $last_insert_id = $this->connection->query($sql, $insert_values, $this->queryOptions);
       }
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       // One of the INSERTs failed, rollback the whole batch.
       $transaction->rollback();
       // Rethrow the exception for the calling code.
diff --git a/core/lib/Drupal/Core/Database/Query/Merge.php b/core/lib/Drupal/Core/Database/Query/Merge.php
index 547a223..93ddee0 100644
--- a/core/lib/Drupal/Core/Database/Query/Merge.php
+++ b/core/lib/Drupal/Core/Database/Query/Merge.php
@@ -10,8 +10,6 @@ namespace Drupal\Core\Database\Query;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Database\Connection;
 
-use Exception;
-
 /**
  * General class for an abstracted MERGE query operation.
  *
@@ -423,7 +421,7 @@ class Merge extends Query implements ConditionInterface {
           $insert->execute();
           return self::STATUS_INSERT;
         }
-        catch (Exception $e) {
+        catch (\Exception $e) {
           // The insert query failed, maybe it's because a racing insert query
           // beat us in inserting the same row. Retry the select query, if it
           // returns a row, ignore the error and continue with the update
@@ -446,7 +444,7 @@ class Merge extends Query implements ConditionInterface {
         return self::STATUS_UPDATE;
       }
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       // Something really wrong happened here, bubble up the exception to the
       // caller.
       $transaction->rollback();
diff --git a/core/lib/Drupal/Core/Database/Statement.php b/core/lib/Drupal/Core/Database/Statement.php
index c5b1735..1ff2ff4 100644
--- a/core/lib/Drupal/Core/Database/Statement.php
+++ b/core/lib/Drupal/Core/Database/Statement.php
@@ -7,9 +7,6 @@
 
 namespace Drupal\Core\Database;
 
-use PDO;
-use PDOStatement;
-
 /**
  * Default implementation of DatabaseStatementInterface.
  *
@@ -21,7 +18,7 @@ use PDOStatement;
  *
  * @see http://php.net/pdostatement
  */
-class Statement extends PDOStatement implements StatementInterface {
+class Statement extends \PDOStatement implements StatementInterface {
 
   /**
    * Reference to the database connection object for this statement.
@@ -34,7 +31,7 @@ class Statement extends PDOStatement implements StatementInterface {
 
   protected function __construct($dbh) {
     $this->dbh = $dbh;
-    $this->setFetchMode(PDO::FETCH_OBJ);
+    $this->setFetchMode(\PDO::FETCH_OBJ);
   }
 
   public function execute($args = array(), $options = array()) {
@@ -43,7 +40,7 @@ class Statement extends PDOStatement implements StatementInterface {
         // Default to an object. Note: db fields will be added to the object
         // before the constructor is run. If you need to assign fields after
         // the constructor is run, see http://drupal.org/node/315092.
-        $this->setFetchMode(PDO::FETCH_CLASS, $options['fetch']);
+        $this->setFetchMode(\PDO::FETCH_CLASS, $options['fetch']);
       }
       else {
         $this->setFetchMode($options['fetch']);
@@ -70,14 +67,14 @@ class Statement extends PDOStatement implements StatementInterface {
   }
 
   public function fetchCol($index = 0) {
-    return $this->fetchAll(PDO::FETCH_COLUMN, $index);
+    return $this->fetchAll(\PDO::FETCH_COLUMN, $index);
   }
 
   public function fetchAllAssoc($key, $fetch = NULL) {
     $return = array();
     if (isset($fetch)) {
       if (is_string($fetch)) {
-        $this->setFetchMode(PDO::FETCH_CLASS, $fetch);
+        $this->setFetchMode(\PDO::FETCH_CLASS, $fetch);
       }
       else {
         $this->setFetchMode($fetch);
@@ -94,7 +91,7 @@ class Statement extends PDOStatement implements StatementInterface {
 
   public function fetchAllKeyed($key_index = 0, $value_index = 1) {
     $return = array();
-    $this->setFetchMode(PDO::FETCH_NUM);
+    $this->setFetchMode(\PDO::FETCH_NUM);
     foreach ($this as $record) {
       $return[$record[$key_index]] = $record[$value_index];
     }
@@ -108,6 +105,6 @@ class Statement extends PDOStatement implements StatementInterface {
 
   public function fetchAssoc() {
     // Call PDOStatement::fetch to fetch the row.
-    return $this->fetch(PDO::FETCH_ASSOC);
+    return $this->fetch(\PDO::FETCH_ASSOC);
   }
 }
diff --git a/core/lib/Drupal/Core/Database/StatementPrefetch.php b/core/lib/Drupal/Core/Database/StatementPrefetch.php
index 18dd582..ddb8225 100644
--- a/core/lib/Drupal/Core/Database/StatementPrefetch.php
+++ b/core/lib/Drupal/Core/Database/StatementPrefetch.php
@@ -8,9 +8,6 @@
 namespace Drupal\Core\Database;
 
 use Drupal\Core\Database\Connection;
-use Iterator;
-use PDO;
-use PDOException;
 
 /**
  * An implementation of DatabaseStatementInterface that prefetches all data.
@@ -18,7 +15,7 @@ use PDOException;
  * This class behaves very similar to a PDOStatement but as it always fetches
  * every row it is possible to manipulate those results.
  */
-class StatementPrefetch implements Iterator, StatementInterface {
+class StatementPrefetch implements \Iterator, StatementInterface {
 
   /**
    * The query string.
@@ -91,7 +88,7 @@ class StatementPrefetch implements Iterator, StatementInterface {
    *
    * @var int
    */
-  protected $fetchStyle = PDO::FETCH_OBJ;
+  protected $fetchStyle = \PDO::FETCH_OBJ;
 
   /**
    * Holds supplementary current fetch options (which will be used by the next fetch).
@@ -110,7 +107,7 @@ class StatementPrefetch implements Iterator, StatementInterface {
    *
    * @var int
    */
-  protected $defaultFetchStyle = PDO::FETCH_OBJ;
+  protected $defaultFetchStyle = \PDO::FETCH_OBJ;
 
   /**
    * Holds supplementary default fetch options.
@@ -146,7 +143,7 @@ class StatementPrefetch implements Iterator, StatementInterface {
         // Default to an object. Note: db fields will be added to the object
         // before the constructor is run. If you need to assign fields after
         // the constructor is run, see http://drupal.org/node/315092.
-        $this->setFetchMode(PDO::FETCH_CLASS, $options['fetch']);
+        $this->setFetchMode(\PDO::FETCH_CLASS, $options['fetch']);
       }
       else {
         $this->setFetchMode($options['fetch']);
@@ -172,7 +169,7 @@ class StatementPrefetch implements Iterator, StatementInterface {
     // Fetch all the data from the reply, in order to release any lock
     // as soon as possible.
     $this->rowCount = $statement->rowCount();
-    $this->data = $statement->fetchAll(PDO::FETCH_ASSOC);
+    $this->data = $statement->fetchAll(\PDO::FETCH_ASSOC);
     // Destroy the statement as soon as possible. See
     // DatabaseConnection_sqlite::PDOPrepare() for explanation.
     unset($statement);
@@ -203,7 +200,7 @@ class StatementPrefetch implements Iterator, StatementInterface {
   protected function throwPDOException() {
     $error_info = $this->dbh->errorInfo();
     // We rebuild a message formatted in the same way as PDO.
-    $exception = new PDOException("SQLSTATE[" . $error_info[0] . "]: General error " . $error_info[1] . ": " . $error_info[2]);
+    $exception = new \PDOException("SQLSTATE[" . $error_info[0] . "]: General error " . $error_info[1] . ": " . $error_info[2]);
     $exception->errorInfo = $error_info;
     throw $exception;
   }
@@ -238,16 +235,16 @@ class StatementPrefetch implements Iterator, StatementInterface {
   public function setFetchMode($fetchStyle, $a2 = NULL, $a3 = NULL) {
     $this->defaultFetchStyle = $fetchStyle;
     switch ($fetchStyle) {
-      case PDO::FETCH_CLASS:
+      case \PDO::FETCH_CLASS:
         $this->defaultFetchOptions['class'] = $a2;
         if ($a3) {
           $this->defaultFetchOptions['constructor_args'] = $a3;
         }
         break;
-      case PDO::FETCH_COLUMN:
+      case \PDO::FETCH_COLUMN:
         $this->defaultFetchOptions['column'] = $a2;
         break;
-      case PDO::FETCH_INTO:
+      case \PDO::FETCH_INTO:
         $this->defaultFetchOptions['object'] = $a2;
         break;
     }
@@ -270,23 +267,23 @@ class StatementPrefetch implements Iterator, StatementInterface {
   public function current() {
     if (isset($this->currentRow)) {
       switch ($this->fetchStyle) {
-        case PDO::FETCH_ASSOC:
+        case \PDO::FETCH_ASSOC:
           return $this->currentRow;
-        case PDO::FETCH_BOTH:
+        case \PDO::FETCH_BOTH:
           // PDO::FETCH_BOTH returns an array indexed by both the column name
           // and the column number.
           return $this->currentRow + array_values($this->currentRow);
-        case PDO::FETCH_NUM:
+        case \PDO::FETCH_NUM:
           return array_values($this->currentRow);
-        case PDO::FETCH_LAZY:
+        case \PDO::FETCH_LAZY:
           // We do not do lazy as everything is fetched already. Fallback to
           // PDO::FETCH_OBJ.
-        case PDO::FETCH_OBJ:
+        case \PDO::FETCH_OBJ:
           return (object) $this->currentRow;
-        case PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE:
+        case \PDO::FETCH_CLASS | \PDO::FETCH_CLASSTYPE:
           $class_name = array_unshift($this->currentRow);
           // Deliberate no break.
-        case PDO::FETCH_CLASS:
+        case \PDO::FETCH_CLASS:
           if (!isset($class_name)) {
             $class_name = $this->fetchOptions['class'];
           }
@@ -301,12 +298,12 @@ class StatementPrefetch implements Iterator, StatementInterface {
             $result->$k = $v;
           }
           return $result;
-        case PDO::FETCH_INTO:
+        case \PDO::FETCH_INTO:
           foreach ($this->currentRow as $k => $v) {
             $this->fetchOptions['object']->$k = $v;
           }
           return $this->fetchOptions['object'];
-        case PDO::FETCH_COLUMN:
+        case \PDO::FETCH_COLUMN:
           if (isset($this->columnNames[$this->fetchOptions['column']])) {
             return $this->currentRow[$k][$this->columnNames[$this->fetchOptions['column']]];
           }
@@ -348,7 +345,7 @@ class StatementPrefetch implements Iterator, StatementInterface {
     return $this->rowCount;
   }
 
-  public function fetch($fetch_style = NULL, $cursor_orientation = PDO::FETCH_ORI_NEXT, $cursor_offset = NULL) {
+  public function fetch($fetch_style = NULL, $cursor_orientation = \PDO::FETCH_ORI_NEXT, $cursor_offset = NULL) {
     if (isset($this->currentRow)) {
       // Set the fetch parameter.
       $this->fetchStyle = isset($fetch_style) ? $fetch_style : $this->defaultFetchStyle;
@@ -392,7 +389,7 @@ class StatementPrefetch implements Iterator, StatementInterface {
         $result = (object) $this->currentRow;
       }
       else {
-        $this->fetchStyle = PDO::FETCH_CLASS;
+        $this->fetchStyle = \PDO::FETCH_CLASS;
         $this->fetchOptions = array('constructor_args' => $constructor_args);
         // Grab the row in the format specified above.
         $result = $this->current();
diff --git a/core/lib/Drupal/Core/Updater/UpdaterException.php b/core/lib/Drupal/Core/Updater/UpdaterException.php
index aee43a6..c859831 100644
--- a/core/lib/Drupal/Core/Updater/UpdaterException.php
+++ b/core/lib/Drupal/Core/Updater/UpdaterException.php
@@ -7,8 +7,6 @@
 
 namespace Drupal\Core\Updater;
 
-use Exception;
-
 /**
  * Defines a Exception class for the Drupal\Core\Updater\Updater class
  * hierarchy.
@@ -17,5 +15,5 @@ use Exception;
  * specific name so that call sites that want to tell the difference can
  * specifically catch these exceptions and treat them differently.
  */
-class UpdaterException extends Exception {
+class UpdaterException extends \Exception {
 }
diff --git a/core/modules/entity/lib/Drupal/entity/EntityController.php b/core/modules/entity/lib/Drupal/entity/EntityController.php
index 3edc4cc..f1cb2f5 100644
--- a/core/modules/entity/lib/Drupal/entity/EntityController.php
+++ b/core/modules/entity/lib/Drupal/entity/EntityController.php
@@ -7,8 +7,6 @@
 
 namespace Drupal\entity;
 
-use PDO;
-
 /**
  * Defines a base entity controller class.
  *
@@ -165,7 +163,7 @@ class EntityController implements EntityControllerInterface {
         // We provide the necessary arguments for PDO to create objects of the
         // specified entity class.
         // @see Drupal\entity\EntityInterface::__construct()
-        $query_result->setFetchMode(PDO::FETCH_CLASS, $this->entityInfo['entity class'], array(array(), $this->entityType));
+        $query_result->setFetchMode(\PDO::FETCH_CLASS, $this->entityInfo['entity class'], array(array(), $this->entityType));
       }
       $queried_entities = $query_result->fetchAllAssoc($this->idKey);
     }
diff --git a/core/modules/entity/lib/Drupal/entity/EntityFieldQueryException.php b/core/modules/entity/lib/Drupal/entity/EntityFieldQueryException.php
index 12f2a1c..ee6f934 100644
--- a/core/modules/entity/lib/Drupal/entity/EntityFieldQueryException.php
+++ b/core/modules/entity/lib/Drupal/entity/EntityFieldQueryException.php
@@ -7,8 +7,6 @@
 
 namespace Drupal\entity;
 
-use Exception;
-
 /**
  * Exception thrown by EntityFieldQuery() on unsupported query syntax.
  *
@@ -16,4 +14,4 @@ use Exception;
  * conditions, and will raise an EntityFieldQueryException when an unsupported
  * condition was specified.
  */
-class EntityFieldQueryException extends Exception { }
+class EntityFieldQueryException extends \Exception { }
diff --git a/core/modules/entity/lib/Drupal/entity/EntityMalformedException.php b/core/modules/entity/lib/Drupal/entity/EntityMalformedException.php
index bd9b500..48d80d0 100644
--- a/core/modules/entity/lib/Drupal/entity/EntityMalformedException.php
+++ b/core/modules/entity/lib/Drupal/entity/EntityMalformedException.php
@@ -7,9 +7,7 @@
 
 namespace Drupal\entity;
 
-use Exception;
-
 /**
  * Defines an exception thrown when a malformed entity is passed.
  */
-class EntityMalformedException extends Exception { }
+class EntityMalformedException extends \Exception { }
diff --git a/core/modules/entity/lib/Drupal/entity/EntityStorageException.php b/core/modules/entity/lib/Drupal/entity/EntityStorageException.php
index dff3e93..573d677 100644
--- a/core/modules/entity/lib/Drupal/entity/EntityStorageException.php
+++ b/core/modules/entity/lib/Drupal/entity/EntityStorageException.php
@@ -7,9 +7,7 @@
 
 namespace Drupal\entity;
 
-use Exception;
-
 /**
  * Defines an exception thrown when storage operations fail.
  */
-class EntityStorageException extends Exception { }
+class EntityStorageException extends \Exception { }
diff --git a/core/modules/node/lib/Drupal/node/NodeStorageController.php b/core/modules/node/lib/Drupal/node/NodeStorageController.php
index dccec71..e439929 100644
--- a/core/modules/node/lib/Drupal/node/NodeStorageController.php
+++ b/core/modules/node/lib/Drupal/node/NodeStorageController.php
@@ -10,7 +10,6 @@ namespace Drupal\node;
 use Drupal\entity\EntityDatabaseStorageController;
 use Drupal\entity\EntityInterface;
 use Drupal\entity\EntityStorageException;
-use Exception;
 
 /**
  * Controller class for nodes.
@@ -72,7 +71,7 @@ class NodeStorageController extends EntityDatabaseStorageController {
       // Ignore slave server temporarily.
       db_ignore_slave();
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $transaction->rollback();
       watchdog_exception($this->entityType, $e);
       throw new EntityStorageException($e->getMessage, $e->getCode, $e);
@@ -119,7 +118,7 @@ class NodeStorageController extends EntityDatabaseStorageController {
 
       return $return;
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $transaction->rollback();
       watchdog_exception($this->entityType, $e);
       throw new EntityStorageException($e->getMessage(), $e->getCode(), $e);
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeCreationTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeCreationTest.php
index f66b2ac..f0574d3 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeCreationTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeCreationTest.php
@@ -8,7 +8,6 @@
 namespace Drupal\node\Tests;
 
 use Drupal\Core\Database\Database;
-use Exception;
 
 class NodeCreationTest extends NodeTestBase {
   public static function getInfo() {
@@ -63,7 +62,7 @@ class NodeCreationTest extends NodeTestBase {
       entity_create('node', $edit)->save();
       $this->fail(t('Expected exception has not been thrown.'));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->pass(t('Expected exception has been thrown.'));
     }
 
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeQueryAlterTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeQueryAlterTest.php
index dc6d95a..624b342 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeQueryAlterTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeQueryAlterTest.php
@@ -7,8 +7,6 @@
 
 namespace Drupal\node\Tests;
 
-use Exception;
-
 /**
  * Tests node_query_node_access_alter().
  */
@@ -84,7 +82,7 @@ class NodeQueryAlterTest extends NodeTestBase {
       $result = $query->execute()->fetchAll();
       $this->assertEqual(count($result), 4, t('User with access can see correct nodes'));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(t('Altered query is malformed'));
     }
   }
@@ -107,7 +105,7 @@ class NodeQueryAlterTest extends NodeTestBase {
       $result = $query->execute()->fetchAll();
       $this->assertEqual(count($result), 0, t('User with no access cannot see nodes'));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(t('Altered query is malformed'));
     }
   }
@@ -130,7 +128,7 @@ class NodeQueryAlterTest extends NodeTestBase {
       $result = $query->execute()->fetchAll();
       $this->assertEqual(count($result), 0, t('User with view-only access cannot edit nodes'));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail($e->getMessage());
       $this->fail((string) $query);
       $this->fail(t('Altered query is malformed'));
@@ -170,7 +168,7 @@ class NodeQueryAlterTest extends NodeTestBase {
       $result = $query->execute()->fetchAll();
       $this->assertEqual(count($result), 0, t('User view privileges are not overridden'));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(t('Altered query is malformed'));
     }
 
@@ -192,7 +190,7 @@ class NodeQueryAlterTest extends NodeTestBase {
       $result = $query->execute()->fetchAll();
       $this->assertEqual(count($result), 4, t('User view privileges are overridden'));
     }
-    catch (Exception $e) {
+    catch (\Exception $e) {
       $this->fail(t('Altered query is malformed'));
     }
     variable_del('node_test_node_access_all_uid');
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index 3bb1e0c..efd05c2 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -9,11 +9,6 @@ namespace Drupal\simpletest;
 
 use Drupal\Core\Database\Database;
 use Drupal\Core\Database\ConnectionNotDefinedException;
-use PDO;
-use stdClass;
-use DOMDocument;
-use DOMXPath;
-use SimpleXMLElement;
 
 /**
  * Test case for typical Drupal tests.
@@ -419,7 +414,7 @@ abstract class WebTestBase extends TestBase {
     }
 
     // Create new role.
-    $role = new stdClass();
+    $role = new \stdClass();
     $role->name = $name;
     user_role_save($role);
     user_role_grant_permissions($role->rid, $permissions);
@@ -672,7 +667,7 @@ abstract class WebTestBase extends TestBase {
     foreach (array('registry', 'registry_file') as $table) {
       // Find the records from the parent database.
       $source_query = $original_connection
-        ->select($table, array(), array('fetch' => PDO::FETCH_ASSOC))
+        ->select($table, array(), array('fetch' => \PDO::FETCH_ASSOC))
         ->fields($table);
 
       $dest_query = $test_connection->insert($table);
@@ -954,7 +949,7 @@ abstract class WebTestBase extends TestBase {
     if (!$this->elements) {
       // DOM can load HTML soup. But, HTML soup can throw warnings, suppress
       // them.
-      $htmlDom = new DOMDocument();
+      $htmlDom = new \DOMDocument();
       @$htmlDom->loadHTML('<?xml encoding="UTF-8">' . $this->drupalGetContent());
       if ($htmlDom) {
         $this->pass(t('Valid HTML found on "@path"', array('@path' => $this->getUrl())), t('Browser'));
@@ -1272,10 +1267,10 @@ abstract class WebTestBase extends TestBase {
       );
       // DOM can load HTML soup. But, HTML soup can throw warnings, suppress
       // them.
-      $dom = new DOMDocument();
+      $dom = new \DOMDocument();
       @$dom->loadHTML($content);
       // XPath allows for finding wrapper nodes better than DOM does.
-      $xpath = new DOMXPath($dom);
+      $xpath = new \DOMXPath($dom);
       foreach ($return as $command) {
         switch ($command['command']) {
           case 'settings':
@@ -1297,7 +1292,7 @@ abstract class WebTestBase extends TestBase {
             }
             if ($wrapperNode) {
               // ajax.js adds an enclosing DIV to work around a Safari bug.
-              $newDom = new DOMDocument();
+              $newDom = new \DOMDocument();
               $newDom->loadHTML('<div>' . $command['data'] . '</div>');
               $newNode = $dom->importNode($newDom->documentElement->firstChild->firstChild, TRUE);
               $method = isset($command['method']) ? $command['method'] : $ajax_settings['method'];
@@ -1630,7 +1625,7 @@ abstract class WebTestBase extends TestBase {
    * @return
    *   Option elements in select.
    */
-  protected function getAllOptions(SimpleXMLElement $element) {
+  protected function getAllOptions(\SimpleXMLElement $element) {
     $options = array();
     // Add all options items.
     foreach ($element->option as $option) {
@@ -2291,7 +2286,7 @@ abstract class WebTestBase extends TestBase {
    * @return
    *   The selected value or FALSE.
    */
-  protected function getSelectedItem(SimpleXMLElement $element) {
+  protected function getSelectedItem(\SimpleXMLElement $element) {
     foreach ($element->children() as $item) {
       if (isset($item['selected'])) {
         return $item['value'];
diff --git a/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsLoggingTest.php b/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsLoggingTest.php
index e0a25f9..01382ca 100644
--- a/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsLoggingTest.php
+++ b/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsLoggingTest.php
@@ -8,7 +8,6 @@
 namespace Drupal\statistics\Tests;
 
 use Drupal\simpletest\WebTestBase;
-use PDO;
 
 /**
  * Tests that logging via statistics_exit() works for all pages.
@@ -72,7 +71,7 @@ class StatisticsLoggingTest extends WebTestBase {
     $stats_path = $base_url . '/' . drupal_get_path('module', 'statistics'). '/statistics.php';
     drupal_http_request($stats_path, array('method' => 'POST', 'data' => $post, 'headers' => $headers, 'timeout' => 10000));
     $this->assertIdentical($this->drupalGetHeader('X-Drupal-Cache'), 'MISS', t('Testing an uncached page.'));
-    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(PDO::FETCH_ASSOC);
+    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(\PDO::FETCH_ASSOC);
     $this->assertTrue(is_array($log) && count($log) == 1, t('Page request was logged.'));
     $this->assertEqual(array_intersect_key($log[0], $expected), $expected);
     $node_counter = statistics_get($this->node->nid);
@@ -83,7 +82,7 @@ class StatisticsLoggingTest extends WebTestBase {
     // Manually calling statistics.php, simulating ajax behavior.
     drupal_http_request($stats_path, array('method' => 'POST', 'data' => $post, 'headers' => $headers, 'timeout' => 10000));
     $this->assertIdentical($this->drupalGetHeader('X-Drupal-Cache'), 'HIT', t('Testing a cached page.'));
-    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(PDO::FETCH_ASSOC);
+    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(\PDO::FETCH_ASSOC);
     $this->assertTrue(is_array($log) && count($log) == 2, t('Page request was logged.'));
     $this->assertEqual(array_intersect_key($log[1], $expected), $expected);
     $node_counter = statistics_get($this->node->nid);
@@ -94,7 +93,7 @@ class StatisticsLoggingTest extends WebTestBase {
     $this->drupalGet($path);
     // Manually calling statistics.php, simulating ajax behavior.
     drupal_http_request($stats_path, array('method' => 'POST', 'data' => $post, 'headers' => $headers, 'timeout' => 10000));
-    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(PDO::FETCH_ASSOC);
+    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(\PDO::FETCH_ASSOC);
     // Check the 6th item since login and account pages are also logged
     $this->assertTrue(is_array($log) && count($log) == 6, t('Page request was logged.'));
     $this->assertEqual(array_intersect_key($log[5], $expected), $expected);
@@ -108,7 +107,7 @@ class StatisticsLoggingTest extends WebTestBase {
       'path' => $path,
     );
     $this->drupalGet($path);
-    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(PDO::FETCH_ASSOC);
+    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(\PDO::FETCH_ASSOC);
     $this->assertTrue(is_array($log) && count($log) == 7, t('Page request was logged.'));
     $this->assertEqual(array_intersect_key($log[6], $expected), $expected);
 
@@ -122,7 +121,7 @@ class StatisticsLoggingTest extends WebTestBase {
 
     // Test that the long path is properly truncated when logged.
     $this->drupalGet($long_path);
-    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(PDO::FETCH_ASSOC);
+    $log = db_query('SELECT * FROM {accesslog}')->fetchAll(\PDO::FETCH_ASSOC);
     $this->assertTrue(is_array($log) && count($log) == 8, 'Page request was logged for a path over 255 characters.');
     $this->assertEqual($log[7]['path'], truncate_utf8($long_path, 255));
 
