code: private void updateSourceValues() {
          JDBCConnectionManager man = JDBCConnectionManager.getJDBCConnectionManager();
          try {
              man.closeConnection();
          } catch (SQLException e) {
              // do nothing
          }
  
          String username = txtDatabaseUsername.getText();
          OBDADataSource currentDataSource = obdaModel.getDatasource();
          currentDataSource.setParameter(RDBMSourceParameterConstants.DATABASE_USERNAME, username);
          String password = new String(txtDatabasePassword.getPassword());
          currentDataSource.setParameter(RDBMSourceParameterConstants.DATABASE_PASSWORD, password);
          String driver = txtJdbcDriver.getSelectedIndex() == 0 ? "" : (String) txtJdbcDriver.getSelectedItem();
          currentDataSource.setParameter(RDBMSourceParameterConstants.DATABASE_DRIVER, driver);
          String url = txtJdbcUrl.getText();
          currentDataSource.setParameter(RDBMSourceParameterConstants.DATABASE_URL, url);
  
          if (url.endsWith(" ")) {
              lblConnectionStatus.setForeground(Color.RED);
              lblConnectionStatus.setText("Warning the URL ends with a white space, this can give rise to connection problems");
          } else if (driver.endsWith(" ")) {
              lblConnectionStatus.setForeground(Color.RED);
              lblConnectionStatus.setText("Warning the Driver class ends with a white space, this can give rise to connection problems");
          } else if (password.endsWith(" ")) {
              lblConnectionStatus.setForeground(Color.RED);
              lblConnectionStatus.setText("Warning the password ends with a white space, this can give rise to connection problems");
          } else if (username.endsWith(" ")) {
              lblConnectionStatus.setForeground(Color.RED);
              lblConnectionStatus.setText("Warning the password ends with a white space, this can give rise to connection problems");
          } else {
              lblConnectionStatus.setText("");
          }
  
          obdaModel.fireSourceParametersUpdated();
      }
docs: GEN-LAST:event_fieldChangeHandler