diff --git a/src/AdapterTest.java b/src/AdapterTest.java
index bcad333..797e772 100644
--- a/src/AdapterTest.java
+++ b/src/AdapterTest.java
@@ -4,11 +4,18 @@ class AdapterTest {
     public static void main(String[] args)
     {
         System.out.println("running...");
+        Engine pEp;
         try {
-            Engine e = new Engine();
+            pEp = new Engine();
         }
         catch (pEpException e) {
+            System.out.println("ERROR: cannot initialize engine");
+            System.exit(1);
         }
+
+        SyncCallbacks callbacks = new SyncCallbacks();
+
         System.out.println("... shutting down");
     }
 }
+
diff --git a/src/Makefile b/src/Makefile
index a468655..a9cb678 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -90,8 +90,8 @@ clean:
 	rm -f throw_pEp_exception.*
 	rm -f org_pEp_jniadapter_Message.cc org_pEp_jniadapter_Engine.cc
 
-AdapterTest.class: AdapterTest.java
-	javac -cp $(JAR) $<
+AdapterTest.class: AdapterTest.java SyncCallbacks.java
+	javac -cp .:$(JAR) $< SyncCallbacks.java
 
 test: AdapterTest.class
 	java AdapterTest
diff --git a/src/SyncCallbacks.java b/src/SyncCallbacks.java
new file mode 100644
index 0000000..8963b71
--- /dev/null
+++ b/src/SyncCallbacks.java
@@ -0,0 +1,14 @@
+import org.pEp.jniadapter.*;
+
+class SyncCallbacks implements Sync.MessageToSendCallback, Sync.notifyHandshakeCallback {
+    public void messageToSend(Message message)
+    {
+        System.out.println(message.getFrom());
+    }
+
+    public void notifyHandshake(Identity myself, Identity partner, SyncHandshakeSignal signal)
+    {
+
+    }
+}
+