diff --git a/src/Resources/config/services.xml b/src/Resources/config/services.xml
index d5829dd48..6109a2299 100644
--- a/src/Resources/config/services.xml
+++ b/src/Resources/config/services.xml
@@ -13,9 +13,7 @@
                 <argument>%kernel.project_dir%</argument>
             </service>
 
-            <service id="maker.autoloader_util" class="Symfony\Bundle\MakerBundle\Util\AutoloaderUtil">
-                <argument>%kernel.project_dir%</argument>
-            </service>
+            <service id="maker.autoloader_util" class="Symfony\Bundle\MakerBundle\Util\AutoloaderUtil" />
 
             <service id="maker.event_registry" class="Symfony\Bundle\MakerBundle\EventRegistry">
                 <argument type="service" id="event_dispatcher" />
diff --git a/src/Util/AutoloaderUtil.php b/src/Util/AutoloaderUtil.php
index 942711d07..02b973e3e 100644
--- a/src/Util/AutoloaderUtil.php
+++ b/src/Util/AutoloaderUtil.php
@@ -12,6 +12,7 @@
 namespace Symfony\Bundle\MakerBundle\Util;
 
 use Composer\Autoload\ClassLoader;
+use Symfony\Component\Debug\DebugClassLoader;
 
 /**
  * @author Ryan Weaver <weaverryan@gmail.com>
@@ -20,13 +21,10 @@
  */
 class AutoloaderUtil
 {
-    private static $classLoader;
-    private $rootDir;
-
-    public function __construct(string $rootDir)
-    {
-        $this->rootDir = $rootDir;
-    }
+    /**
+     * @var ClassLoader
+     */
+    private $classLoader;
 
     /**
      * Returns the relative path to where a new class should live.
@@ -76,16 +74,27 @@ public function getNamespacePrefixForClass(string $className): string
 
     private function getClassLoader(): ClassLoader
     {
-        if (null === self::$classLoader) {
-            $autoloadPath = $this->rootDir.'/vendor/autoload.php';
-
-            if (!file_exists($autoloadPath)) {
-                throw new \Exception(sprintf('Could not find the autoload file: "%s"', $autoloadPath));
+        if (null === $this->classLoader) {
+            $autoloadFunctions = spl_autoload_functions();
+            foreach ($autoloadFunctions as $autoloader) {
+                if (is_array($autoloader) && isset($autoloader[0]) && is_object($autoloader[0])) {
+                    if ($autoloader[0] instanceof ClassLoader) {
+                        $this->classLoader = $autoloader[0];
+                        break;
+                    }
+                    if ($autoloader[0] instanceof DebugClassLoader
+                        && is_array($autoloader[0]->getClassLoader())
+                        && $autoloader[0]->getClassLoader()[0] instanceof ClassLoader) {
+                        $this->classLoader = $autoloader[0]->getClassLoader()[0];
+                        break;
+                    }
+                }
+            }
+            if (null === $this->classLoader) {
+                throw new \Exception('Composer ClassLoader not found!');
             }
-
-            self::$classLoader = require $autoloadPath;
         }
 
-        return self::$classLoader;
+        return $this->classLoader;
     }
 }
diff --git a/tests/Util/AutoloaderUtilTest.php b/tests/Util/AutoloaderUtilTest.php
index 286b3392b..d9d1b0ed0 100644
--- a/tests/Util/AutoloaderUtilTest.php
+++ b/tests/Util/AutoloaderUtilTest.php
@@ -2,10 +2,10 @@
 
 namespace Symfony\Bundle\MakerBundle\Tests\Util;
 
+use Composer\Autoload\ClassLoader;
 use PHPUnit\Framework\TestCase;
 use Symfony\Bundle\MakerBundle\Util\AutoloaderUtil;
 use Symfony\Component\Filesystem\Filesystem;
-use Symfony\Component\Process\Process;
 
 class AutoloaderUtilTest extends TestCase
 {
@@ -28,42 +28,42 @@ public static function setupPaths()
 
     public function testGetPathForFutureClass()
     {
+        $classLoader = new ClassLoader();
         $composerJson = [
             'autoload' => [
                 'psr-4' => [
-                    'Also\\In\\Src\\' => 'src/SubDir',
-                    'App\\' => 'src/',
-                    'Other\\Namespace\\' => 'lib',
-                    '' => 'fallback_dir',
+                    'Also\\In\\Src\\' => '/src/SubDir',
+                    'App\\' => '/src',
+                    'Other\\Namespace\\' => '/lib',
+                    '' => '/fallback_dir',
                 ],
                 'psr-0' => [
-                    'Psr0\\Package' => 'lib/other',
+                    'Psr0\\Package' => '/lib/other',
                 ],
             ],
         ];
 
-        $fs = new Filesystem();
-        if (!file_exists(self::$currentRootDir)) {
-            $fs->mkdir(self::$currentRootDir);
+        foreach ($composerJson['autoload'] as $psr => $dirs) {
+            foreach ($dirs as $prefix => $path) {
+                if ($psr == 'psr-4') {
+                    $classLoader->addPsr4($prefix, self::$currentRootDir.$path);
+                } else {
+                    $classLoader->add($prefix, self::$currentRootDir.$path);
+                }
+            }
         }
 
-        $fs->remove(self::$currentRootDir.'/vendor');
-        file_put_contents(
-            self::$currentRootDir.'/composer.json',
-            json_encode($composerJson, JSON_PRETTY_PRINT)
-        );
-        $process = new Process('composer dump-autoload', self::$currentRootDir);
-        $process->run();
-        if (!$process->isSuccessful()) {
-            throw new \Exception('Error running composer dump-autoload: '.$process->getErrorOutput());
-        }
+        $reflection = new \ReflectionClass(AutoloaderUtil::class);
+        $property = $reflection->getProperty('classLoader');
+        $property->setAccessible(true);
+
+        $autoloaderUtil = new AutoloaderUtil();
 
+        $property->setValue($autoloaderUtil, $classLoader);
 
-        $autoloaderUtil = new AutoloaderUtil(self::$currentRootDir);
         foreach ($this->getPathForFutureClassTests() as $className => $expectedPath) {
             $this->assertSame(
-                // the paths will start in vendor/composer and be relative
-                str_replace('\\', '/', self::$currentRootDir.'/vendor/composer/../../'.$expectedPath),
+                str_replace('\\', '/', self::$currentRootDir.'/'.$expectedPath),
                 // normalize slashes for Windows comparison
                 str_replace('\\', '/', $autoloaderUtil->getPathForFutureClass($className)),
                 sprintf('class "%s" should have been in path "%s"', $className, $expectedPath)
@@ -71,6 +71,16 @@ public function testGetPathForFutureClass()
         }
     }
 
+    public function testCanFindClassLoader()
+    {
+        $reflection = new \ReflectionClass(AutoloaderUtil::class);
+        $method = $reflection->getMethod('getClassLoader');
+        $method->setAccessible(true);
+        $autoloaderUtil = new AutoloaderUtil();
+        $autoloader = $method->invoke($autoloaderUtil);
+        $this->assertInstanceOf(ClassLoader::class, $autoloader, 'Wrong ClassLoader found');
+    }
+
     public function getPathForFutureClassTests()
     {
         return [