keep alive message shoud not be a interface

src/ei/engine/network/message/KeepAliveMessage.java

@@ -0,0 +1,16 @@
+package ei.engine.network.message;
+
+import ei.engine.network.message.type.SystemMessage;
+
+/**
+ * Tells the destination that the 
+ * source is still online
+ * 
+ * @author Ziver
+ *
+ */
+public class KeepAliveMessage extends Message implements SystemMessage{
+
+	private static final long serialVersionUID = 1L;
+
+}

src/ei/engine/network/message/type/KeepAliveMessage.java

@@ -1,12 +0,0 @@
-package ei.engine.network.message.type;
-
-/**
- * Tells the destination that the 
- * source is still online
- * 
- * @author Ziver
- *
- */
-public interface KeepAliveMessage {
-
-}