diff --git a/.env b/.env
index b98cab5..9f26605 100755
--- a/.env
+++ b/.env
@@ -17,6 +17,7 @@
 # app env
 #---------------------------------------------
 VALIDATOR_PATH=%kernel.project_dir%/bin/validator-cli.jar
+VALIDATOR_JAVA_OPTS='-Xms256m -Xmx2g'
 DATA_DIR=%kernel.project_dir%/var/data
 
 #---------------------------------------------
diff --git a/config/services.yaml b/config/services.yaml
index 4be69aa..beeb23b 100755
--- a/config/services.yaml
+++ b/config/services.yaml
@@ -17,6 +17,7 @@ services:
       $validationsDir: "%env(resolve:DATA_DIR)%/validations"
       $projectDir: "%kernel.project_dir%"
       $validatorPath: "%ignf_validator.path%"
+      $validatorJavaOpts: "%env(resolve:VALIDATOR_JAVA_OPTS)%"
       $gmlasConfigPath: "%env(resolve:GMLAS_CONFIG)%"
 
   # makes classes in src/ available to be used as services
diff --git a/config/services_test.yaml b/config/services_test.yaml
index 9f6ab29..b100ece 100644
--- a/config/services_test.yaml
+++ b/config/services_test.yaml
@@ -6,6 +6,7 @@ services:
       $validationsDir: "%env(resolve:DATA_DIR)%/validations-test"
       $projectDir: "%kernel.project_dir%"
       $validatorPath: "%ignf_validator.path%"
+      $validatorJavaOpts: "%env(resolve:VALIDATOR_JAVA_OPTS)%"
       $gmlasConfigPath: "%env(resolve:GMLAS_CONFIG)%"
 
   App\:
diff --git a/src/Validation/ValidatorCLI.php b/src/Validation/ValidatorCLI.php
index 4e6ea44..82ce3cc 100644
--- a/src/Validation/ValidatorCLI.php
+++ b/src/Validation/ValidatorCLI.php
@@ -24,6 +24,11 @@ class ValidatorCLI
      */
     private $validatorPath;
 
+    /**
+     * @var string
+     */
+    private $validatorJavaOpts;
+
     /**
      * GMLAS_CONFIG environment variable for validator-cli.jar to avoid lower case renaming for GML validation.
      *
@@ -39,6 +44,7 @@ class ValidatorCLI
     public function __construct(
         ValidationsStorage $storage,
         $validatorPath,
+        $validatorJavaOpts,
         $gmlasConfigPath,
         LoggerInterface $logger
     ) {
@@ -47,6 +53,7 @@ public function __construct(
         if ( ! file_exists($this->validatorPath) ){
             throw new ValidatorNotFoundException($this->validatorPath);
         }
+        $this->validatorJavaOpts = $validatorJavaOpts;
         $this->gmlasConfigPath = $gmlasConfigPath;
         $this->logger = $logger;
     }
@@ -66,9 +73,16 @@ public function process(Validation $validation)
         $env = $_ENV;
         $env['GMLAS_CONFIG'] = $this->gmlasConfigPath;
 
-        $args = $this->reconstructArgs($validation);
+        
         $sourceDataDir = $validationDirectory.'/'.$validation->getDatasetName();
-        $cmd = ['java', '-jar', $this->validatorPath, 'document_validator', '--input', $sourceDataDir];
+        $cmd = ['java'];
+        $cmd = \array_merge($cmd, explode(' ',$this->validatorJavaOpts));
+        $cmd = \array_merge($cmd,[
+            '-jar', $this->validatorPath, 
+            'document_validator', 
+            '--input', $sourceDataDir
+        ]);
+        $args = $this->reconstructArgs($validation);
         $cmd = \array_merge($cmd, $args);
 
         // executing validation program