Java code to be called from C sample

android/src/org/pEp/jniadapter/Sync.java

@@ -0,0 +1,21 @@
+package org.pEp.jniadapter;
+
+import org.pEp.jniadapter.Identity;
+import org.pEp.jniadapter.Message;
+import org.pEp.jniadapter.pEpException;
+
+/**
+ * Created by huss on 02/09/16.
+ */
+
+public interface Sync {
+
+    interface MessageToSendCallback {
+        void messageToSend(Message message);
+    }
+
+    interface showHandshakeCallback {
+        void showHandshake(Identity myself, Identity partner);
+    }
+
+}

src/org/pEp/jniadapter/AbstractEngine.java

@@ -10,6 +10,9 @@ abstract class AbstractEngine implements AutoCloseable {
         System.loadLibrary("pEpJNI");
     }
 
+
+    private Sync.MessageToSendCallback messageToSendCallback;
+    private Sync.showHandshakeCallback showHandshakeCallback;
     private native void init() throws pEpException;
     private native void release();
 
@@ -143,5 +146,30 @@ abstract class AbstractEngine implements AutoCloseable {
 
         return result;
     }
+
+    public void setMessageToSendCallback(Sync.MessageToSendCallback messageToSendCallback) {
+        this.messageToSendCallback = messageToSendCallback;
+    }
+
+    public void setShowHandshakeCallback(Sync.showHandshakeCallback showHandshakeCallback) {
+        this.showHandshakeCallback = showHandshakeCallback;
+    }
+
+    //Call From C is not a good name only for sample purposes
+    public void callFrom_C_ShowHandshake(Identity myself, Identity partner) {
+        if (showHandshakeCallback != null) {
+            showHandshakeCallback.showHandshake(myself, partner);
+        } else {
+            throw new RuntimeException("Callback not set");
+        }
+    }
+
+    public void callFrom_C_MessageToSend (Message message) {
+        if (messageToSendCallback != null) {
+            messageToSendCallback.messageToSend(message);
+        } else {
+            throw new RuntimeException("Callback not set");
+        }
+    }
 }