diff --git a/typo3/sysext/core/Classes/Cache/Backend/ApcBackend.php b/typo3/sysext/core/Classes/Cache/Backend/ApcBackend.php
index ea77c6851461f7d7378a3b38cb1286e39ba7a14a..d8a82bb1f29b4fdceba16a24e4b49669a54b0f66 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/ApcBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/ApcBackend.php
@@ -14,7 +14,11 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Exception\InvalidDataException;
+use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
 use TYPO3\CMS\Core\Core\Environment;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
 
 /**
  * A caching backend which stores cache entries by using APC.
@@ -72,15 +76,15 @@ class ApcBackend extends AbstractBackend implements TaggableBackendInterface
      *
      * @param string $context Unused, for backward compatibility only
      * @param array $options Configuration options - unused here
-     * @throws \TYPO3\CMS\Core\Cache\Exception
+     * @throws Exception
      */
     public function __construct($context, array $options = [])
     {
         if (!extension_loaded('apc')) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The PHP extension "apc" or "apcu" must be installed and loaded in order to use the APC backend.', 1232985414);
+            throw new Exception('The PHP extension "apc" or "apcu" must be installed and loaded in order to use the APC backend.', 1232985414);
         }
         if (PHP_SAPI === 'cli' && ini_get('apc.enable_cli') == 0) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The APC backend cannot be used because apc is disabled on CLI.', 1232985415);
+            throw new Exception('The APC backend cannot be used because apc is disabled on CLI.', 1232985415);
         }
         parent::__construct($context, $options);
     }
@@ -88,13 +92,13 @@ class ApcBackend extends AbstractBackend implements TaggableBackendInterface
     /**
      * Initializes the identifier prefix when setting the cache.
      *
-     * @param \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache
+     * @param FrontendInterface $cache
      */
-    public function setCache(\TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache)
+    public function setCache(FrontendInterface $cache)
     {
         parent::setCache($cache);
         $processUser = $this->getCurrentUserData();
-        $pathHash = \TYPO3\CMS\Core\Utility\GeneralUtility::shortMD5(Environment::getProjectPath() . $processUser['name'] . $this->context . $cache->getIdentifier(), 12);
+        $pathHash = GeneralUtility::shortMD5(Environment::getProjectPath() . $processUser['name'] . $this->context . $cache->getIdentifier(), 12);
         $this->setIdentifierPrefix('TYPO3_' . $pathHash);
     }
 
@@ -116,17 +120,17 @@ class ApcBackend extends AbstractBackend implements TaggableBackendInterface
      * @param string $data The data to be stored
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
-     * @throws \TYPO3\CMS\Core\Cache\Exception if no cache frontend has been set.
-     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException if $data is not a string
+     * @throws Exception if no cache frontend has been set.
+     * @throws InvalidDataException if $data is not a string
      * @api
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
     {
-        if (!$this->cache instanceof \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('No cache frontend has been set yet via setCache().', 1232986818);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('No cache frontend has been set yet via setCache().', 1232986818);
         }
         if (!is_string($data)) {
-            throw new \TYPO3\CMS\Core\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1232986825);
+            throw new InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1232986825);
         }
         $tags[] = '%APCBE%' . $this->cacheIdentifier;
         $expiration = $lifetime ?? $this->defaultLifetime;
@@ -217,13 +221,13 @@ class ApcBackend extends AbstractBackend implements TaggableBackendInterface
     /**
      * Removes all cache entries of this cache.
      *
-     * @throws \TYPO3\CMS\Core\Cache\Exception
+     * @throws Exception
      * @api
      */
     public function flush()
     {
-        if (!$this->cache instanceof \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('Yet no cache frontend has been set via setCache().', 1232986971);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('Yet no cache frontend has been set via setCache().', 1232986971);
         }
         $this->flushByTag('%APCBE%' . $this->cacheIdentifier);
     }
diff --git a/typo3/sysext/core/Classes/Cache/Backend/ApcuBackend.php b/typo3/sysext/core/Classes/Cache/Backend/ApcuBackend.php
index a0076ab0f21f4d237b298f7555a2e9edfaff442d..2ada163c294379121537b3bfe42e80169d571657 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/ApcuBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/ApcuBackend.php
@@ -14,7 +14,9 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
-use TYPO3\CMS\Core\Cache;
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Exception\InvalidDataException;
+use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
 use TYPO3\CMS\Core\Core\Environment;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 
@@ -74,15 +76,15 @@ class ApcuBackend extends AbstractBackend implements TaggableBackendInterface
      *
      * @param string $context Unused, for backward compatibility only
      * @param array $options Configuration options - unused here
-     * @throws Cache\Exception
+     * @throws Exception
      */
     public function __construct($context, array $options = [])
     {
         if (!extension_loaded('apcu')) {
-            throw new Cache\Exception('The PHP extension "apcu" must be installed and loaded in order to use the APCu backend.', 1232985914);
+            throw new Exception('The PHP extension "apcu" must be installed and loaded in order to use the APCu backend.', 1232985914);
         }
         if (PHP_SAPI === 'cli' && ini_get('apc.enable_cli') == 0) {
-            throw new Cache\Exception('The APCu backend cannot be used because apcu is disabled on CLI.', 1232985915);
+            throw new Exception('The APCu backend cannot be used because apcu is disabled on CLI.', 1232985915);
         }
         parent::__construct($context, $options);
     }
@@ -90,9 +92,9 @@ class ApcuBackend extends AbstractBackend implements TaggableBackendInterface
     /**
      * Initializes the identifier prefix when setting the cache.
      *
-     * @param \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache
+     * @param FrontendInterface $cache
      */
-    public function setCache(\TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache)
+    public function setCache(FrontendInterface $cache)
     {
         parent::setCache($cache);
         $processUser = $this->getCurrentUserData();
@@ -118,17 +120,17 @@ class ApcuBackend extends AbstractBackend implements TaggableBackendInterface
      * @param string $data The data to be stored
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
-     * @throws Cache\Exception if no cache frontend has been set.
-     * @throws Cache\Exception\InvalidDataException if $data is not a string
+     * @throws Exception if no cache frontend has been set.
+     * @throws InvalidDataException if $data is not a string
      * @api
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
     {
-        if (!$this->cache instanceof Cache\Frontend\FrontendInterface) {
-            throw new Cache\Exception('No cache frontend has been set yet via setCache().', 1232986118);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('No cache frontend has been set yet via setCache().', 1232986118);
         }
         if (!is_string($data)) {
-            throw new Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1232986125);
+            throw new InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1232986125);
         }
         $tags[] = '%APCBE%' . $this->cacheIdentifier;
         $expiration = $lifetime ?? $this->defaultLifetime;
@@ -219,13 +221,13 @@ class ApcuBackend extends AbstractBackend implements TaggableBackendInterface
     /**
      * Removes all cache entries of this cache.
      *
-     * @throws Cache\Exception
+     * @throws Exception
      * @api
      */
     public function flush()
     {
-        if (!$this->cache instanceof Cache\Frontend\FrontendInterface) {
-            throw new Cache\Exception('Yet no cache frontend has been set via setCache().', 1232986571);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('Yet no cache frontend has been set via setCache().', 1232986571);
         }
         $this->flushByTag('%APCBE%' . $this->cacheIdentifier);
     }
diff --git a/typo3/sysext/core/Classes/Cache/Backend/BackendInterface.php b/typo3/sysext/core/Classes/Cache/Backend/BackendInterface.php
index 815d9cfd2039bab5fbb95ee6a54fcc2aeac1f84f..0e1bf1aca61624705a4881689332d3e43f2a81e7 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/BackendInterface.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/BackendInterface.php
@@ -14,6 +14,8 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache;
+
 /**
  * A contract for a Cache Backend
  * @api
@@ -23,10 +25,10 @@ interface BackendInterface
     /**
      * Sets a reference to the cache frontend which uses this backend
      *
-     * @param \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache The frontend for this backend
+     * @param Cache\Frontend\FrontendInterface $cache The frontend for this backend
      * @api
      */
-    public function setCache(\TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache);
+    public function setCache(Cache\Frontend\FrontendInterface $cache);
 
     /**
      * Saves data in the cache.
diff --git a/typo3/sysext/core/Classes/Cache/Backend/FileBackend.php b/typo3/sysext/core/Classes/Cache/Backend/FileBackend.php
index 3118a1395cdf1b2ed717f7710db9ddfe0b57c57e..3adc246fa94deef19cf56b8cd052628caffa28b4 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/FileBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/FileBackend.php
@@ -14,6 +14,9 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Exception\InvalidDataException;
+use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
 use TYPO3\CMS\Core\Service\OpcodeCacheService;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Core\Utility\PathUtility;
@@ -24,7 +27,7 @@ use TYPO3\CMS\Core\Utility\StringUtility;
  *
  * @api
  */
-class FileBackend extends \TYPO3\CMS\Core\Cache\Backend\SimpleFileBackend implements \TYPO3\CMS\Core\Cache\Backend\FreezableBackendInterface, \TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface
+class FileBackend extends SimpleFileBackend implements FreezableBackendInterface, TaggableBackendInterface
 {
     const SEPARATOR = '^';
     const EXPIRYTIME_FORMAT = 'YmdHis';
@@ -98,9 +101,9 @@ class FileBackend extends \TYPO3\CMS\Core\Cache\Backend\SimpleFileBackend implem
      * This method also detects if this backend is frozen and sets the internal
      * flag accordingly.
      *
-     * @param \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache The cache frontend
+     * @param FrontendInterface $cache The cache frontend
      */
-    public function setCache(\TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache)
+    public function setCache(FrontendInterface $cache)
     {
         parent::setCache($cache);
         if (file_exists($this->cacheDirectory . 'FrozenCache.data')) {
@@ -117,15 +120,15 @@ class FileBackend extends \TYPO3\CMS\Core\Cache\Backend\SimpleFileBackend implem
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
      * @throws \RuntimeException
-     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException if the directory does not exist or is not writable or exceeds the maximum allowed path length, or if no cache frontend has been set.
-     * @throws \TYPO3\CMS\Core\Cache\Exception if the directory does not exist or is not writable or exceeds the maximum allowed path length, or if no cache frontend has been set.
+     * @throws InvalidDataException if the directory does not exist or is not writable or exceeds the maximum allowed path length, or if no cache frontend has been set.
+     * @throws Exception if the directory does not exist or is not writable or exceeds the maximum allowed path length, or if no cache frontend has been set.
      * @throws \InvalidArgumentException
      * @api
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
     {
         if (!is_string($data)) {
-            throw new \TYPO3\CMS\Core\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1204481674);
+            throw new InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1204481674);
         }
         if ($entryIdentifier !== PathUtility::basename($entryIdentifier)) {
             throw new \InvalidArgumentException('The specified entry identifier must not contain a path segment.', 1282073032);
@@ -142,9 +145,9 @@ class FileBackend extends \TYPO3\CMS\Core\Cache\Backend\SimpleFileBackend implem
         $expiryTime = $lifetime === 0 ? 0 : $GLOBALS['EXEC_TIME'] + $lifetime;
         $metaData = str_pad($expiryTime, self::EXPIRYTIME_LENGTH) . implode(' ', $tags) . str_pad(strlen($data), self::DATASIZE_DIGITS);
         $result = file_put_contents($temporaryCacheEntryPathAndFilename, $data . $metaData);
-        \TYPO3\CMS\Core\Utility\GeneralUtility::fixPermissions($temporaryCacheEntryPathAndFilename);
+        GeneralUtility::fixPermissions($temporaryCacheEntryPathAndFilename);
         if ($result === false) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The temporary cache file "' . $temporaryCacheEntryPathAndFilename . '" could not be written.', 1204026251);
+            throw new Exception('The temporary cache file "' . $temporaryCacheEntryPathAndFilename . '" could not be written.', 1204026251);
         }
         $i = 0;
         $cacheEntryPathAndFilename = $this->cacheDirectory . $entryIdentifier . $this->cacheEntryFileExtension;
@@ -152,7 +155,7 @@ class FileBackend extends \TYPO3\CMS\Core\Cache\Backend\SimpleFileBackend implem
             $i++;
         }
         if ($result === false) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The cache file "' . $cacheEntryPathAndFilename . '" could not be written.', 1222361632);
+            throw new Exception('The cache file "' . $cacheEntryPathAndFilename . '" could not be written.', 1222361632);
         }
         if ($this->cacheEntryFileExtension === '.php') {
             GeneralUtility::makeInstance(OpcodeCacheService::class)->clearAllActive($cacheEntryPathAndFilename);
@@ -252,7 +255,7 @@ class FileBackend extends \TYPO3\CMS\Core\Cache\Backend\SimpleFileBackend implem
         $entryIdentifiers = [];
         $now = $GLOBALS['EXEC_TIME'];
         $cacheEntryFileExtensionLength = strlen($this->cacheEntryFileExtension);
-        for ($directoryIterator = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\DirectoryIterator::class, $this->cacheDirectory); $directoryIterator->valid(); $directoryIterator->next()) {
+        for ($directoryIterator = GeneralUtility::makeInstance(\DirectoryIterator::class, $this->cacheDirectory); $directoryIterator->valid(); $directoryIterator->next()) {
             if ($directoryIterator->isDot()) {
                 continue;
             }
diff --git a/typo3/sysext/core/Classes/Cache/Backend/FreezableBackendInterface.php b/typo3/sysext/core/Classes/Cache/Backend/FreezableBackendInterface.php
index dc72335493b433d2690809743e88ec1ae65b0c6f..e7035530552bd83672bb4e5ca1c43d5bcecfa80b 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/FreezableBackendInterface.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/FreezableBackendInterface.php
@@ -19,7 +19,7 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  *
  * @api
  */
-interface FreezableBackendInterface extends \TYPO3\CMS\Core\Cache\Backend\BackendInterface
+interface FreezableBackendInterface extends BackendInterface
 {
     /**
      * Freezes this cache backend.
diff --git a/typo3/sysext/core/Classes/Cache/Backend/NullBackend.php b/typo3/sysext/core/Classes/Cache/Backend/NullBackend.php
index 76d84aea09f438ef88e8b7c34151d19fb28494f8..62cc4c62a3e46f239655248b707de778c3fa95b8 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/NullBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/NullBackend.php
@@ -19,7 +19,7 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  *
  * @api
  */
-class NullBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend implements \TYPO3\CMS\Core\Cache\Backend\PhpCapableBackendInterface, \TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface
+class NullBackend extends AbstractBackend implements PhpCapableBackendInterface, TaggableBackendInterface
 {
     /**
      * Acts as if it would save data
diff --git a/typo3/sysext/core/Classes/Cache/Backend/PdoBackend.php b/typo3/sysext/core/Classes/Cache/Backend/PdoBackend.php
index 48e7a4bccb777c3bb5ca0bbe86b943dd1006b69c..3ad8446edae076b8f948c8700f7a3a41fae60768 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/PdoBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/PdoBackend.php
@@ -14,11 +14,18 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Exception\InvalidDataException;
+use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
+use TYPO3\CMS\Core\Database\PdoHelper;
+use TYPO3\CMS\Core\Utility\ExtensionManagementUtility;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
 /**
  * A PDO database cache backend
  * @api
  */
-class PdoBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend implements \TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface
+class PdoBackend extends AbstractBackend implements TaggableBackendInterface
 {
     /**
      * @var string
@@ -93,31 +100,31 @@ class PdoBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend implement
      * @param string $data The data to be stored
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
-     * @throws \TYPO3\CMS\Core\Cache\Exception if no cache frontend has been set.
+     * @throws Exception if no cache frontend has been set.
      * @throws \InvalidArgumentException if the identifier is not valid
-     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException if $data is not a string
+     * @throws InvalidDataException if $data is not a string
      * @api
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
     {
-        if (!$this->cache instanceof \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('No cache frontend has been set yet via setCache().', 1259515600);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('No cache frontend has been set yet via setCache().', 1259515600);
         }
         if (!is_string($data)) {
-            throw new \TYPO3\CMS\Core\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1259515601);
+            throw new InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1259515601);
         }
         $this->remove($entryIdentifier);
         $lifetime = $lifetime ?? $this->defaultLifetime;
         $statementHandle = $this->databaseHandle->prepare('INSERT INTO "cache" ("identifier", "context", "cache", "created", "lifetime", "content") VALUES (?, ?, ?, ?, ?, ?)');
         $result = $statementHandle->execute([$entryIdentifier, $this->context, $this->cacheIdentifier, $GLOBALS['EXEC_TIME'], $lifetime, $data]);
         if ($result === false) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The cache entry "' . $entryIdentifier . '" could not be written.', 1259530791);
+            throw new Exception('The cache entry "' . $entryIdentifier . '" could not be written.', 1259530791);
         }
         $statementHandle = $this->databaseHandle->prepare('INSERT INTO "tags" ("identifier", "context", "cache", "tag") VALUES (?, ?, ?, ?)');
         foreach ($tags as $tag) {
             $result = $statementHandle->execute([$entryIdentifier, $this->context, $this->cacheIdentifier, $tag]);
             if ($result === false) {
-                throw new \TYPO3\CMS\Core\Cache\Exception('The tag "' . $tag . ' for cache entry "' . $entryIdentifier . '" could not be written.', 1259530751);
+                throw new Exception('The tag "' . $tag . ' for cache entry "' . $entryIdentifier . '" could not be written.', 1259530751);
             }
         }
     }
@@ -244,10 +251,10 @@ class PdoBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend implement
             $splitdsn = explode(':', $this->dataSourceName, 2);
             $this->pdoDriver = $splitdsn[0];
             if ($this->pdoDriver === 'sqlite' && !file_exists($splitdsn[1])) {
-                $this->databaseHandle = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\PDO::class, $this->dataSourceName, $this->username, $this->password);
+                $this->databaseHandle = GeneralUtility::makeInstance(\PDO::class, $this->dataSourceName, $this->username, $this->password);
                 $this->createCacheTables();
             } else {
-                $this->databaseHandle = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\PDO::class, $this->dataSourceName, $this->username, $this->password);
+                $this->databaseHandle = GeneralUtility::makeInstance(\PDO::class, $this->dataSourceName, $this->username, $this->password);
             }
             $this->databaseHandle->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
             if (substr($this->pdoDriver, 0, 5) === 'mysql') {
@@ -266,10 +273,10 @@ class PdoBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend implement
     protected function createCacheTables()
     {
         try {
-            \TYPO3\CMS\Core\Database\PdoHelper::importSql(
+            PdoHelper::importSql(
                 $this->databaseHandle,
                 $this->pdoDriver,
-                \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::extPath('core') .
+                ExtensionManagementUtility::extPath('core') .
                 'Resources/Private/Sql/Cache/Backend/PdoBackendCacheAndTags.sql'
             );
         } catch (\PDOException $e) {
diff --git a/typo3/sysext/core/Classes/Cache/Backend/PhpCapableBackendInterface.php b/typo3/sysext/core/Classes/Cache/Backend/PhpCapableBackendInterface.php
index b98a362879a690db9f6112995d335ea0ee4b3c25..b71cc2bedf943e77e5265cd35159de70b65b8e7a 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/PhpCapableBackendInterface.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/PhpCapableBackendInterface.php
@@ -20,7 +20,7 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  *
  * @api
  */
-interface PhpCapableBackendInterface extends \TYPO3\CMS\Core\Cache\Backend\BackendInterface
+interface PhpCapableBackendInterface extends BackendInterface
 {
     /**
      * Loads PHP code from the cache and require_onces it right away.
diff --git a/typo3/sysext/core/Classes/Cache/Backend/RedisBackend.php b/typo3/sysext/core/Classes/Cache/Backend/RedisBackend.php
index 9598807ed1e30df3e6a25d7fb47bf48462f55fde..90ab2cef4c35106c3f835bcac5d5720bb10831c9 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/RedisBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/RedisBackend.php
@@ -14,6 +14,8 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Exception\InvalidDataException;
 use TYPO3\CMS\Core\Utility\StringUtility;
 
 /**
@@ -134,12 +136,12 @@ class RedisBackend extends AbstractBackend implements TaggableBackendInterface
      *
      * @param string $context Unused, for backward compatibility only
      * @param array $options Configuration options
-     * @throws \TYPO3\CMS\Core\Cache\Exception if php redis module is not loaded
+     * @throws Exception if php redis module is not loaded
      */
     public function __construct($context, array $options = [])
     {
         if (!extension_loaded('redis')) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The PHP extension "redis" must be installed and loaded in order to use the redis backend.', 1279462933);
+            throw new Exception('The PHP extension "redis" must be installed and loaded in order to use the redis backend.', 1279462933);
         }
         parent::__construct($context, $options);
     }
@@ -147,7 +149,7 @@ class RedisBackend extends AbstractBackend implements TaggableBackendInterface
     /**
      * Initializes the redis backend
      *
-     * @throws \TYPO3\CMS\Core\Cache\Exception if access to redis with password is denied or if database selection fails
+     * @throws Exception if access to redis with password is denied or if database selection fails
      */
     public function initializeObject()
     {
@@ -165,13 +167,13 @@ class RedisBackend extends AbstractBackend implements TaggableBackendInterface
             if ($this->password !== '') {
                 $success = $this->redis->auth($this->password);
                 if (!$success) {
-                    throw new \TYPO3\CMS\Core\Cache\Exception('The given password was not accepted by the redis server.', 1279765134);
+                    throw new Exception('The given password was not accepted by the redis server.', 1279765134);
                 }
             }
             if ($this->database >= 0) {
                 $success = $this->redis->select($this->database);
                 if (!$success) {
-                    throw new \TYPO3\CMS\Core\Cache\Exception('The given database "' . $this->database . '" could not be selected.', 1279765144);
+                    throw new Exception('The given database "' . $this->database . '" could not be selected.', 1279765144);
                 }
             }
         }
@@ -308,7 +310,7 @@ class RedisBackend extends AbstractBackend implements TaggableBackendInterface
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, default lifetime is used. "0" means unlimited lifetime.
      * @throws \InvalidArgumentException if identifier is not valid
-     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException if data is not a string
+     * @throws InvalidDataException if data is not a string
      * @api
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
@@ -317,7 +319,7 @@ class RedisBackend extends AbstractBackend implements TaggableBackendInterface
             throw new \InvalidArgumentException('The specified identifier is of type "' . gettype($entryIdentifier) . '" which can\'t be converted to string.', 1377006651);
         }
         if (!is_string($data)) {
-            throw new \TYPO3\CMS\Core\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1279469941);
+            throw new InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1279469941);
         }
         $lifetime = $lifetime ?? $this->defaultLifetime;
         if (!is_int($lifetime)) {
diff --git a/typo3/sysext/core/Classes/Cache/Backend/SimpleFileBackend.php b/typo3/sysext/core/Classes/Cache/Backend/SimpleFileBackend.php
index 158d2e97956f3708c73b66916387089b8334f442..3c7359122fcc34e035345a9ce3b85f3bae47279b 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/SimpleFileBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/SimpleFileBackend.php
@@ -14,6 +14,10 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Exception\InvalidDataException;
+use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
+use TYPO3\CMS\Core\Cache\Frontend\PhpFrontend;
 use TYPO3\CMS\Core\Core\Environment;
 use TYPO3\CMS\Core\Service\OpcodeCacheService;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
@@ -70,10 +74,10 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
      * Sets a reference to the cache frontend which uses this backend and
      * initializes the default cache directory.
      *
-     * @param \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache The cache frontend
-     * @throws \TYPO3\CMS\Core\Cache\Exception
+     * @param FrontendInterface $cache The cache frontend
+     * @throws Exception
      */
-    public function setCache(\TYPO3\CMS\Core\Cache\Frontend\FrontendInterface $cache)
+    public function setCache(FrontendInterface $cache)
     {
         parent::setCache($cache);
         if (empty($this->temporaryCacheDirectory)) {
@@ -83,16 +87,16 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
         } else {
             $temporaryCacheDirectory = $this->temporaryCacheDirectory;
         }
-        $codeOrData = $cache instanceof \TYPO3\CMS\Core\Cache\Frontend\PhpFrontend ? 'code' : 'data';
+        $codeOrData = $cache instanceof PhpFrontend ? 'code' : 'data';
         $finalCacheDirectory = $temporaryCacheDirectory . 'cache/' . $codeOrData . '/' . $this->cacheIdentifier . '/';
         if (!is_dir($finalCacheDirectory)) {
             $this->createFinalCacheDirectory($finalCacheDirectory);
         }
         unset($this->temporaryCacheDirectory);
         $this->cacheDirectory = $finalCacheDirectory;
-        $this->cacheEntryFileExtension = $cache instanceof \TYPO3\CMS\Core\Cache\Frontend\PhpFrontend ? '.php' : '';
+        $this->cacheEntryFileExtension = $cache instanceof PhpFrontend ? '.php' : '';
         if (strlen($this->cacheDirectory) + 23 > PHP_MAXPATHLEN) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The length of the temporary cache file path "' . $this->cacheDirectory . '" exceeds the ' . 'maximum path length of ' . (PHP_MAXPATHLEN - 23) . '. Please consider ' . 'setting the temporaryDirectoryBase option to a shorter path.', 1248710426);
+            throw new Exception('The length of the temporary cache file path "' . $this->cacheDirectory . '" exceeds the ' . 'maximum path length of ' . (PHP_MAXPATHLEN - 23) . '. Please consider ' . 'setting the temporaryDirectoryBase option to a shorter path.', 1248710426);
         }
     }
 
@@ -107,7 +111,7 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
      * option was handled.
      *
      * @param string $cacheDirectory The cache base directory. If a relative path
-     * @throws \TYPO3\CMS\Core\Cache\Exception if the directory is not within allowed
+     * @throws Exception if the directory is not within allowed
      */
     public function setCacheDirectory($cacheDirectory)
     {
@@ -141,7 +145,7 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
                 if ($basedir[strlen($basedir) - 1] !== '/') {
                     $basedir .= '/';
                 }
-                if (\TYPO3\CMS\Core\Utility\GeneralUtility::isFirstPartOfStr($cacheDirectory, $basedir)) {
+                if (GeneralUtility::isFirstPartOfStr($cacheDirectory, $basedir)) {
                     $documentRoot = $basedir;
                     $cacheDirectory = str_replace($basedir, '', $cacheDirectory);
                     $cacheDirectoryInBaseDir = true;
@@ -149,7 +153,7 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
                 }
             }
             if (!$cacheDirectoryInBaseDir) {
-                throw new \TYPO3\CMS\Core\Cache\Exception(
+                throw new Exception(
                     'Open_basedir restriction in effect. The directory "' . $cacheDirectory . '" is not in an allowed path.',
                     1476045417
                 );
@@ -176,17 +180,17 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
      * Create the final cache directory if it does not exist.
      *
      * @param string $finalCacheDirectory Absolute path to final cache directory
-     * @throws \TYPO3\CMS\Core\Cache\Exception If directory is not writable after creation
+     * @throws Exception If directory is not writable after creation
      */
     protected function createFinalCacheDirectory($finalCacheDirectory)
     {
         try {
-            \TYPO3\CMS\Core\Utility\GeneralUtility::mkdir_deep($finalCacheDirectory);
+            GeneralUtility::mkdir_deep($finalCacheDirectory);
         } catch (\RuntimeException $e) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The directory "' . $finalCacheDirectory . '" can not be created.', 1303669848, $e);
+            throw new Exception('The directory "' . $finalCacheDirectory . '" can not be created.', 1303669848, $e);
         }
         if (!is_writable($finalCacheDirectory)) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The directory "' . $finalCacheDirectory . '" is not writable.', 1203965200);
+            throw new Exception('The directory "' . $finalCacheDirectory . '" is not writable.', 1203965200);
         }
     }
 
@@ -208,15 +212,15 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
      * @param string $data The data to be stored
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime This cache backend does not support life times
-     * @throws \TYPO3\CMS\Core\Cache\Exception if the directory does not exist or is not writable or exceeds the maximum allowed path length, or if no cache frontend has been set.
-     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException if the data to bes stored is not a string.
+     * @throws Exception if the directory does not exist or is not writable or exceeds the maximum allowed path length, or if no cache frontend has been set.
+     * @throws InvalidDataException if the data to bes stored is not a string.
      * @throws \InvalidArgumentException
      * @api
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
     {
         if (!is_string($data)) {
-            throw new \TYPO3\CMS\Core\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1334756734);
+            throw new InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1334756734);
         }
         if ($entryIdentifier !== PathUtility::basename($entryIdentifier)) {
             throw new \InvalidArgumentException('The specified entry identifier must not contain a path segment.', 1334756735);
@@ -226,9 +230,9 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
         }
         $temporaryCacheEntryPathAndFilename = $this->cacheDirectory . StringUtility::getUniqueId() . '.temp';
         $result = file_put_contents($temporaryCacheEntryPathAndFilename, $data);
-        \TYPO3\CMS\Core\Utility\GeneralUtility::fixPermissions($temporaryCacheEntryPathAndFilename);
+        GeneralUtility::fixPermissions($temporaryCacheEntryPathAndFilename);
         if ($result === false) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The temporary cache file "' . $temporaryCacheEntryPathAndFilename . '" could not be written.', 1334756737);
+            throw new Exception('The temporary cache file "' . $temporaryCacheEntryPathAndFilename . '" could not be written.', 1334756737);
         }
         $cacheEntryPathAndFilename = $this->cacheDirectory . $entryIdentifier . $this->cacheEntryFileExtension;
         rename($temporaryCacheEntryPathAndFilename, $cacheEntryPathAndFilename);
@@ -305,7 +309,7 @@ class SimpleFileBackend extends AbstractBackend implements PhpCapableBackendInte
      */
     public function flush()
     {
-        \TYPO3\CMS\Core\Utility\GeneralUtility::flushDirectory($this->cacheDirectory, true);
+        GeneralUtility::flushDirectory($this->cacheDirectory, true);
     }
 
     /**
diff --git a/typo3/sysext/core/Classes/Cache/Backend/TaggableBackendInterface.php b/typo3/sysext/core/Classes/Cache/Backend/TaggableBackendInterface.php
index e800133a8f5c6b116bf9ea7c4b78eef86ba05458..dfea18ac4c06f891dcfecea0a46cf94dd027e008 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/TaggableBackendInterface.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/TaggableBackendInterface.php
@@ -19,7 +19,7 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  *
  * @api
  */
-interface TaggableBackendInterface extends \TYPO3\CMS\Core\Cache\Backend\BackendInterface
+interface TaggableBackendInterface extends BackendInterface
 {
     /**
      * Removes all cache entries of this cache which are tagged by the specified tag.
diff --git a/typo3/sysext/core/Classes/Cache/Backend/TransientMemoryBackend.php b/typo3/sysext/core/Classes/Cache/Backend/TransientMemoryBackend.php
index e1199648cef6474901cb7248fffa63e5bfbf23cb..15b5814b176dfb8b63be235483fae4f14f2f519b 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/TransientMemoryBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/TransientMemoryBackend.php
@@ -14,12 +14,15 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
+
 /**
  * A caching backend which stores cache entries during one script run.
  *
  * @api
  */
-class TransientMemoryBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend implements TaggableBackendInterface, TransientBackendInterface
+class TransientMemoryBackend extends AbstractBackend implements TaggableBackendInterface, TransientBackendInterface
 {
     /**
      * @var array
@@ -38,14 +41,13 @@ class TransientMemoryBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBacke
      * @param string $data The data to be stored
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
-     * @throws \TYPO3\CMS\Core\Cache\Exception if no cache frontend has been set.
-     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException
+     * @throws Exception if no cache frontend has been set.
      * @api
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
     {
-        if (!$this->cache instanceof \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('No cache frontend has been set yet via setCache().', 1238244992);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('No cache frontend has been set yet via setCache().', 1238244992);
         }
         $this->entries[$entryIdentifier] = $data;
         foreach ($tags as $tag) {
diff --git a/typo3/sysext/core/Classes/Cache/Backend/WincacheBackend.php b/typo3/sysext/core/Classes/Cache/Backend/WincacheBackend.php
index 107dcf3e3aeac5e99866a24984ee650c2c8f0252..a13c1fff3513ff53a56e3d1d2fd9be197639c278 100644
--- a/typo3/sysext/core/Classes/Cache/Backend/WincacheBackend.php
+++ b/typo3/sysext/core/Classes/Cache/Backend/WincacheBackend.php
@@ -14,6 +14,10 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Cache\Exception;
+use TYPO3\CMS\Core\Cache\Exception\InvalidDataException;
+use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
+
 /**
  * A caching backend which stores cache entries by using wincache.
  *
@@ -34,7 +38,7 @@ namespace TYPO3\CMS\Core\Cache\Backend;
  * This prefix makes sure that keys from the different installations do not
  * conflict.
  */
-class WincacheBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend implements \TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface
+class WincacheBackend extends AbstractBackend implements TaggableBackendInterface
 {
     /**
      * A prefix to separate stored data from other data possible stored in the wincache
@@ -48,12 +52,12 @@ class WincacheBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend impl
      *
      * @param string $context Unused, for backward compatibility only
      * @param array $options Configuration options
-     * @throws \TYPO3\CMS\Core\Cache\Exception If wincache PHP extension is not loaded
+     * @throws Exception If wincache PHP extension is not loaded
      */
     public function __construct($context, array $options = [])
     {
         if (!extension_loaded('wincache')) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('The PHP extension "wincache" must be installed and loaded in order to use the wincache backend.', 1343331520);
+            throw new Exception('The PHP extension "wincache" must be installed and loaded in order to use the wincache backend.', 1343331520);
         }
         parent::__construct($context, $options);
     }
@@ -65,17 +69,17 @@ class WincacheBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend impl
      * @param string $data The data to be stored
      * @param array $tags Tags to associate with this cache entry
      * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
-     * @throws \TYPO3\CMS\Core\Cache\Exception if no cache frontend has been set
+     * @throws Exception if no cache frontend has been set
      * @throws \InvalidArgumentException if the identifier is not valid
-     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException if $data is not a string
+     * @throws InvalidDataException if $data is not a string
      */
     public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
     {
-        if (!$this->cache instanceof \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('No cache frontend has been set yet via setCache().', 1343331521);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('No cache frontend has been set yet via setCache().', 1343331521);
         }
         if (!is_string($data)) {
-            throw new \TYPO3\CMS\Core\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1343331522);
+            throw new InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1343331522);
         }
         $tags[] = '%WCBE%' . $this->cache->getIdentifier();
         $expiration = $lifetime ?? $this->defaultLifetime;
@@ -84,7 +88,7 @@ class WincacheBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend impl
             $this->removeIdentifierFromAllTags($entryIdentifier);
             $this->addIdentifierToTags($entryIdentifier, $tags);
         } else {
-            throw new \TYPO3\CMS\Core\Cache\Exception('Could not set value.', 1343331523);
+            throw new Exception('Could not set value.', 1343331523);
         }
     }
 
@@ -160,12 +164,12 @@ class WincacheBackend extends \TYPO3\CMS\Core\Cache\Backend\AbstractBackend impl
     /**
      * Removes all cache entries of this cache
      *
-     * @throws \TYPO3\CMS\Core\Cache\Exception
+     * @throws Exception
      */
     public function flush()
     {
-        if (!$this->cache instanceof \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface) {
-            throw new \TYPO3\CMS\Core\Cache\Exception('Yet no cache frontend has been set via setCache().', 1343331524);
+        if (!$this->cache instanceof FrontendInterface) {
+            throw new Exception('Yet no cache frontend has been set via setCache().', 1343331524);
         }
         $this->flushByTag('%WCBE%' . $this->cache->getIdentifier());
     }