Finally fixed the bug that was haunting me for the last week.

demo/src/main/java/ch/dissem/bitmessage/demo/Application.java

@@ -28,6 +28,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.UnsupportedEncodingException;
+import java.net.InetAddress;
 import java.util.List;
 import java.util.Scanner;
 
@@ -40,7 +41,7 @@ public class Application {
 
     private BitmessageContext ctx;
 
-    public Application() {
+    public Application(String syncServer, int syncPort) {
         JdbcConfig jdbcConfig = new JdbcConfig();
         ctx = new BitmessageContext.Builder()
                 .addressRepo(new JdbcAddressRepository(jdbcConfig))
@@ -63,7 +64,9 @@ public class Application {
                 })
                 .build();
 
-        ctx.startup();
+        if (syncServer == null) {
+            ctx.startup();
+        }
 
         scanner = new Scanner(System.in);
 
@@ -75,6 +78,9 @@ public class Application {
             System.out.println("c) contacts");
             System.out.println("s) subscriptions");
             System.out.println("m) messages");
+            if (syncServer != null) {
+                System.out.println("y) sync");
+            }
             System.out.println("?) info");
             System.out.println("e) exit");
 
@@ -99,6 +105,9 @@ public class Application {
                         break;
                     case "e":
                         break;
+                    case "y":
+                        ctx.synchronize(InetAddress.getByName(syncServer), syncPort, 120, true);
+                        break;
                     default:
                         System.out.println("Unknown command. Please try again.");
                 }

demo/src/main/java/ch/dissem/bitmessage/demo/Main.java

@@ -64,7 +64,7 @@ public class Main {
                 new WifImporter(ctx, options.importWIF).importAll();
             }
         } else {
-            new Application();
+            new Application(options.syncServer, options.syncPort);
         }
     }
 
@@ -74,5 +74,11 @@ public class Main {
 
         @Option(name = "-export", usage = "Export to WIF file.")
         private File exportWIF;
+
+        @Option(name = "-syncServer", usage = "Use manual synchronization with the given server instead of starting a full node.")
+        private String syncServer;
+
+        @Option(name = "-syncPort", usage = "Port to use for synchronisation")
+        private int syncPort = 8444;
     }
 }