Written javadoc for many classes

Signed-off-by: Rogiel <rogiel@rogiel.com>

src/main/java/com/l2jserver/service/database/DatabaseService.java

@@ -2,6 +2,12 @@ package com.l2jserver.service.database;
 
 import com.l2jserver.service.Service;
 
+/**
+ * The database service manages connection between the {@link DataAccessObject}
+ * implementation and the database.
+ * 
+ * @author <a href="http://www.rogiel.com">Rogiel</a>
+ */
 public interface DatabaseService extends Service {
 
 }