#467 data-bus: add missing javadoc

data-bus/src/main/java/com/iluwatar/databus/AbstractDataType.java

@@ -25,7 +25,7 @@ SOFTWARE.
 package com.iluwatar.databus;
 
 /**
- * .
+ * Base for data to send via the Data-Bus.
  *
  * @author Paul Campbell (pcampbell@kemitix.net)
  */

data-bus/src/main/java/com/iluwatar/databus/data/MessageData.java

@@ -27,7 +27,7 @@ import com.iluwatar.databus.AbstractDataType;
 import com.iluwatar.databus.DataType;
 
 /**
- * .
+ * An event raised when a string message is sent.
  *
  * @author Paul Campbell (pcampbell@kemitix.net)
  */

data-bus/src/main/java/com/iluwatar/databus/data/StoppingData.java

@@ -29,7 +29,7 @@ import com.iluwatar.databus.DataType;
 import java.time.LocalDateTime;
 
 /**
- * .
+ * An event raised when applications stops, containing the stop time of the application.
  *
  * @author Paul Campbell (pcampbell@kemitix.net)
  */