dependencies: #2449 bump maven-checkstyle-plugin from 3.1.0 to 3.2.0 + resolve chec… (#2464)

* #2449 bump maven-checkstyle-plugin from 3.1.0 to 3.2.0 + resolve checkstyle issues

* remove FileSelectorJFrame.java to resolve checkstyle issue

* remove FileSelectorJFrame.java to resolve checkstyle issue

* remove FileSelectorJFrame.java to resolve checkstyle issue

* add refactored file with correct filename to resolve checkstyle issue

* add the test data

* change filenames from JFrame to Jframe for checkstyle

* fix code smell from  sonar report

* add new testcases to improve the test coverage

* remove code smell

domain-model/src/main/java/com/iluwatar/domainmodel/CustomerDaoImpl.java

@@ -30,9 +30,11 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Optional;
 import javax.sql.DataSource;
-
 import org.joda.money.Money;
 
+/**
+ * Implementations for database operations of Customer.
+ */
 public class CustomerDaoImpl implements CustomerDao {
 
   private final DataSource dataSource;