diff --git a/ragconnect.base/src/main/jastadd/Errors.jrag b/ragconnect.base/src/main/jastadd/Errors.jrag
index 1aa3666c2b19bf446667f1a763bfb4824aa44f25..770e506cc5c0145a0ba9979d57a1086a399ed39e 100644
--- a/ragconnect.base/src/main/jastadd/Errors.jrag
+++ b/ragconnect.base/src/main/jastadd/Errors.jrag
@@ -1,7 +1,3 @@
-import java.util.Set;
-import java.util.TreeSet;
-import java.util.LinkedList;
-
 aspect Errors {
   coll Set<ErrorMessage> RagConnect.errors()
     [new TreeSet<ErrorMessage>()]
diff --git a/ragconnect.base/src/main/jastadd/Imports.jadd b/ragconnect.base/src/main/jastadd/Imports.jadd
new file mode 100644
index 0000000000000000000000000000000000000000..27fc9a5cfc5bbcbd2772fe35548bda22ab888e01
--- /dev/null
+++ b/ragconnect.base/src/main/jastadd/Imports.jadd
@@ -0,0 +1,5 @@
+import java.util.*;
+
+aspect Imports {
+  // empty
+}
diff --git a/ragconnect.base/src/main/jastadd/Navigation.jrag b/ragconnect.base/src/main/jastadd/Navigation.jrag
index d3890f7d22a195127e7688435f9168aa64a37eac..437f65196c2dc3b8c4f5a112a23e80608084a063 100644
--- a/ragconnect.base/src/main/jastadd/Navigation.jrag
+++ b/ragconnect.base/src/main/jastadd/Navigation.jrag
@@ -1,6 +1,3 @@
-import java.util.List;
-import java.util.ArrayList;
-
 aspect RagConnectNavigation {
 
   // --- program ---
diff --git a/ragconnect.base/src/main/resources/MqttHandler.jadd b/ragconnect.base/src/main/resources/MqttHandler.jadd
index e017f7848a8e33c2a9ce4964a33e435aeecebf7a..dd473dc8cf02fc65411551ac643b3e170b1f7e99 100644
--- a/ragconnect.base/src/main/resources/MqttHandler.jadd
+++ b/ragconnect.base/src/main/resources/MqttHandler.jadd
@@ -239,7 +239,7 @@ public class MqttHandler {
 
   private java.util.List<java.util.function.BiConsumer<String, byte[]>> callbacksFor(String topicString) {
     java.util.List<java.util.function.BiConsumer<String, byte[]>> result = new java.util.ArrayList<>();
-    List<BiConsumer<String, byte[]>> normalCallbackList = normalCallbacks.get(topicString);
+    java.util.List<java.util.function.BiConsumer<String, byte[]>> normalCallbackList = normalCallbacks.get(topicString);
     if (normalCallbackList != null) {
       result.addAll(normalCallbackList);
     }
@@ -305,7 +305,7 @@ public class MqttHandler {
       if (pairToAddTo == null) {
         pairToAddTo = new PatternCallbackListPair();
         pairToAddTo.pattern = java.util.regex.Pattern.compile(regex);
-        pairToAddTo.callbacks = new ArrayList<>();
+        pairToAddTo.callbacks = new java.util.ArrayList<>();
         wildcardCallbacks.add(pairToAddTo);
       }
       needSubscribe = pairToAddTo.callbacks.isEmpty();
@@ -321,7 +321,7 @@ public class MqttHandler {
     }
     if (needSubscribe) {
       // subscribe at broker
-      CountDownLatch operationFinished = new CountDownLatch(1);
+      java.util.concurrent.CountDownLatch operationFinished = new java.util.concurrent.CountDownLatch(1);
       java.util.concurrent.atomic.AtomicReference<Boolean> success = new java.util.concurrent.atomic.AtomicReference<>(true);
       org.fusesource.mqtt.client.Topic[] topicArray = { new org.fusesource.mqtt.client.Topic(topic, this.qos) };
       connection.getDispatchQueue().execute(() -> {
@@ -341,7 +341,7 @@ public class MqttHandler {
         });
       });
       try {
-        operationFinished.await(2, TimeUnit.SECONDS);
+        operationFinished.await(2, java.util.concurrent.TimeUnit.SECONDS);
         return success.get();
       } catch (InterruptedException e) {
         return false;