static {
            URL = "https://website.com";
            DEFAULT_WAIT_TIME = 60;
            SYSTEM_ID = "IDnumber";
            USERNAME = "Username1";
            PASSWORD = "Password1";
    }

import static org.junit.Assert.fail;

import java.util.concurrent.TimeUnit;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.openqa.selenium.*;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;

public class Login {
    private WebDriver driver;
    private String baseURL;
    private StringBuffer verificationErrors = new StringBuffer();

        @Before
        public void setUp() throws Exception {
            //driver = new FirefoxDriver();
            //baseURL = Environment.URL;
            driver.manage().timeouts().implicitlyWait(Environment.DEFAULT_WAIT_TIME, TimeUnit.SECONDS);
        }

        public static void doLogin(WebDriver driver, String baseURL) {
            WebDriverWait wait = new WebDriverWait(driver, Environment.DEFAULT_WAIT_TIME);
            System.out.println("Log in to trunk...");
            driver.get(baseURL);

            wait.until(ExpectedConditions.presenceOfElementLocated(By.id("company_id")));
            if (driver.findElement(By.xpath("//div[span='Log In']/span")).isEnabled()) {
                System.out.println("    1 - 'Login' page is opened");
            }   else {
                    System.out.println("    !ERROR! - Can NOT open 'Login' page");
                    driver.findElement(By.id("This is to throw exception if Can NOT open 'Login' page"));
                }
            driver.findElement(By.id("company_id")).clear();
            driver.findElement(By.id("company_id")).sendKeys(Environment.SYSTEM_ID);
            driver.findElement(By.xpath("//input[@name='username']")).clear();
            driver.findElement(By.xpath("//input[@name='username']")).sendKeys(Environment.USERNAME);
            driver.findElement(By.id("c_password")).clear();
            driver.findElement(By.id("c_password")).sendKeys(Environment.PASSWORD);
            System.out.println("    2 - Info filled");

            //I removed the rest of the code that finishes the login because
            //I don't think it is needed for demonstration

        }

        @Test
        public void main() {
            doLogin(driver, baseURL);
        }

        @After
        public void tearDown() throws Exception {
                driver.quit();
                    String verificationErrorString = verificationErrors.toString();
                        if (!"".equals(verificationErrorString)) {
                        fail(verificationErrorString);
                        }
        }
}

import static org.junit.Assert.fail;

import java.util.concurrent.TimeUnit;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.ie.InternetExplorerDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.Select;
import org.openqa.selenium.support.ui.WebDriverWait;

public class Transaction {
    private WebDriver driver;
    private String baseURL;
    private StringBuffer verificationErrors = new StringBuffer();

    public static String country = "22";
    public static String ammount = "500";

        @Before
        public void setUp() throws Exception {
//          System.setProperty("webdriver.ie.driver", "../IEDriverServer.exe");
//          driver = new InternetExplorerDriver();
            driver = new FirefoxDriver();
            baseURL = Environment.URL;

            driver.manage().timeouts().implicitlyWait(Environment.DEFAULT_WAIT_TIME, TimeUnit.SECONDS);
        }

        public static void doTransaction(WebDriver driver) {
            WebDriverWait wait = new WebDriverWait(driver, Environment.DEFAULT_WAIT_TIME);
            System.out.println("Performing transaction...");


        // This is where the transaction code is ......

        }

        @Test
        public void transaction() {
        //Login first
            Login.doLogin(driver, baseURL);

        // Transaction
            doTransaction(driver);
        }

        @After
        public void tearDown() throws Exception {
                driver.quit();
                    String verificationErrorString = verificationErrors.toString();
                        if (!"".equals(verificationErrorString)) {
                        fail(verificationErrorString);
                        }
        }
}

<suite>
    <test name="firstTest">
        <parameter name="username" value="username1"/>
        <parameter name="password" value="password1"/>
        ....
    </test>
        <test name="secondTest">
        <parameter name="username" value="username2"/>
        <parameter name="password" value="password2"/>
        ....
    </test>
</suite>

@Parameters({"username", "password"})
  @BeforeTest
  public void beforeTest(String username, String password) {
    this.getDriver().get("http://mypage.com");
    this.getDriver().findElement(By.id("usernameInputField")).sendKeys(username);
    this.getDriver().findElement(By.id("passwordInputField")).sendKeys(password);
    ...
  }