How to pass from Jasper to Scriptlet the Username/password of the Data Adapters?

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.naming.NamingException;

import net.sf.jasperreports.engine.JRDefaultScriptlet;
import net.sf.jasperreports.engine.JRParameter;
import net.sf.jasperreports.engine.JRScriptletException;
import net.sf.jasperreports.engine.fill.JRFillParameter;

public class ConnectionManager extends JRDefaultScriptlet{
    private static String url = "jdbc:oracle:thin:@host:port:SERVICE_NAME";
    private static String driverName = "oracle.jdbc.driver.OracleDriver";      
    private static String username = "username";  
    private static String password = "pswd";
    private static Connection con;
    private Connection conn;
    private Object server;

    // EXAMPLE 1: I try to use but it doesn't work and I don't know WHY? I don't understand why the people who exposed him in a forum and it works.
    public Connection getConnection_pruebas() throws JRScriptletException {

        if (getParameterValue(JRFillParameter.REPORT_CONNECTION) != null) {
          conn= ((Connection) getParameterValue(JRParameter.REPORT_CONNECTION) );
        } else {
          throw new RuntimeException("No db-connection configured in the report!");
        }

        return conn;
    }   

    // EXAMPLE 2: I try to use but it doesn't work

    public static Connection getConnection() throws JRScriptletException, ClassNotFoundException {
        try {
            Class.forName(driverName).newInstance();
            try {
                con= DriverManager.getConnection(url, username, password);
            } catch (SQLException ex) {
                // log an exception. fro example:
                //System.out.println("Failed to create the database connection.");                
            }
        } catch (ClassNotFoundException ex) {
            System.out.println("ClassNotFound: "
                + ex.getCause() );
        } finally {
            if (con != null) {
               try{
                  con.close();
               } catch(Exception e){
                  e.printStackTrace();
               }
            }
         }
       
         return con;
    }  

    public static void main(String[] args) throws JRScriptletException, SQLException {               

        Connection con = getConnection();
       
    }   
}