diff --git a/dao/src/main/java/com/iluwatar/dao/CustomException.java b/dao/src/main/java/com/iluwatar/dao/CustomException.java
new file mode 100644
index 000000000..fd291b605
--- /dev/null
+++ b/dao/src/main/java/com/iluwatar/dao/CustomException.java
@@ -0,0 +1,43 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.dao;
+
+/**
+ * 
+ * Custom exception
+ *
+ */
+public class CustomException extends Exception {
+
+  private static final long serialVersionUID = 1L;
+
+  public CustomException() {}
+
+  public CustomException(String message) {
+    super(message);
+  }
+  
+  public CustomException(String message, Throwable cause) {
+    super(message, cause);
+  }
+}
diff --git a/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java b/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java
index 6e93207cc..fa2e411da 100644
--- a/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java
+++ b/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java
@@ -36,12 +36,16 @@ import java.util.stream.StreamSupport;
 
 import javax.sql.DataSource;
 
+import org.apache.log4j.Logger;
+
 /**
- * An implementation of {@link CustomerDao} that persists customers in RDBMS. 
+ * An implementation of {@link CustomerDao} that persists customers in RDBMS.
  *
  */
 public class DbCustomerDao implements CustomerDao {
 
+  private static final Logger LOGGER = Logger.getLogger(DbCustomerDao.class);
+
   private final DataSource dataSource;
 
   /**
@@ -65,8 +69,8 @@ public class DbCustomerDao implements CustomerDao {
     Connection connection;
     try {
       connection = getConnection();
-      PreparedStatement statement = connection.prepareStatement("SELECT * FROM CUSTOMERS");  //NOSONAR
-      ResultSet resultSet = statement.executeQuery(); //NOSONAR
+      PreparedStatement statement = connection.prepareStatement("SELECT * FROM CUSTOMERS"); // NOSONAR
+      ResultSet resultSet = statement.executeQuery(); // NOSONAR
       return StreamSupport.stream(new Spliterators.AbstractSpliterator<Customer>(Long.MAX_VALUE, 
           Spliterator.ORDERED) {
 
@@ -79,12 +83,12 @@ public class DbCustomerDao implements CustomerDao {
             action.accept(createCustomer(resultSet));
             return true;
           } catch (SQLException e) {
-            throw new RuntimeException(e);
+            throw new RuntimeException(e); // NOSONAR
           }
         }
       }, false).onClose(() -> mutedClose(connection, statement, resultSet));
     } catch (SQLException e) {
-      throw new Exception(e.getMessage(), e);
+      throw new CustomException(e.getMessage(), e);
     }
   }
 
@@ -98,7 +102,7 @@ public class DbCustomerDao implements CustomerDao {
       statement.close();
       connection.close();
     } catch (SQLException e) {
-      e.printStackTrace();
+      LOGGER.info("Exception thrown " + e.getMessage());
     }
   }
 
@@ -113,19 +117,26 @@ public class DbCustomerDao implements CustomerDao {
    */
   @Override
   public Optional<Customer> getById(int id) throws Exception {
+
+    ResultSet resultSet = null;
+
     try (Connection connection = getConnection();
         PreparedStatement statement = 
             connection.prepareStatement("SELECT * FROM CUSTOMERS WHERE ID = ?")) {
 
       statement.setInt(1, id);
-      ResultSet resultSet = statement.executeQuery();
+      resultSet = statement.executeQuery();
       if (resultSet.next()) {
         return Optional.of(createCustomer(resultSet));
       } else {
         return Optional.empty();
       }
     } catch (SQLException ex) {
-      throw new Exception(ex.getMessage(), ex);
+      throw new CustomException(ex.getMessage(), ex);
+    } finally {
+      if (resultSet != null) {
+        resultSet.close();
+      }
     }
   }
 
@@ -147,7 +158,7 @@ public class DbCustomerDao implements CustomerDao {
       statement.execute();
       return true;
     } catch (SQLException ex) {
-      throw new Exception(ex.getMessage(), ex);
+      throw new CustomException(ex.getMessage(), ex);
     }
   }
 
@@ -164,7 +175,7 @@ public class DbCustomerDao implements CustomerDao {
       statement.setInt(3, customer.getId());
       return statement.executeUpdate() > 0;
     } catch (SQLException ex) {
-      throw new Exception(ex.getMessage(), ex);
+      throw new CustomException(ex.getMessage(), ex);
     }
   }
 
@@ -179,7 +190,7 @@ public class DbCustomerDao implements CustomerDao {
       statement.setInt(1, customer.getId());
       return statement.executeUpdate() > 0;
     } catch (SQLException ex) {
-      throw new Exception(ex.getMessage(), ex);
+      throw new CustomException(ex.getMessage(), ex);
     }
   }
 }