diff --git a/js-test/build.gradle b/js-test/build.gradle
index 0a52b1b1c9bf72e8554ba038e994158686cf9cac..822f38775920a5718880d92a9cbccb603f217d58 100644
--- a/js-test/build.gradle
+++ b/js-test/build.gradle
@@ -76,7 +76,9 @@ test {
     useTestNG()
     options.suites('source/java/tests.xml')
 
-    jvmArgs '-Xmx2048m', '-Dorg.eclipse.jetty.util.log.class=org.eclipse.jetty.util.log.StrErrLog', '-Duser.timezone=Europe/Zurich', '-Xdebug', '-Xrunjdwp:transport=dt_socket,address=20010,server=y,suspend=n'
+    jvmArgs '-Xmx2048m', '-Dorg.eclipse.jetty.util.log.class=org.eclipse.jetty.util.log.StrErrLog', '-Duser.timezone=Europe/Zurich',
+        '-Xdebug', '-Xrunjdwp:transport=dt_socket,address=20010,server=y,suspend=n', 
+        '--add-opens=java.base/java.util=ALL-UNNAMED'
     
     testLogging.showStandardStreams = true
     ignoreFailures = false
diff --git a/ui-test/build.gradle b/ui-test/build.gradle
index 97b04cf744e5ca762e1ac10d3949f46a1d5bd1cb..6956b628444486575c3a4f0a8f08d65bd45d058c 100644
--- a/ui-test/build.gradle
+++ b/ui-test/build.gradle
@@ -64,7 +64,7 @@ test {
     useTestNG()
     options.suites('source/java/tests.xml')    
 
-    jvmArgs '-Xmx2048m', '-Duser.timezone=Europe/Zurich'
+    jvmArgs '-Xmx2048m', '-Duser.timezone=Europe/Zurich', '--add-opens=java.base/java.util=ALL-UNNAMED'
     
     testLogging.showStandardStreams = true
     ignoreFailures = true