Selenium:Specifying multiple groups at test method level

Specifying multiple groups at test method level:
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package testngdemo;

import org.testng.annotations.Test;

public class GroupDemo {

@Test(groups={"regression"})
public void testScript1() {
System.out.println("regression");

}

@Test(groups="regression")
public void testScript2() {
System.out.println("regression");

}
@Test(groups="regression")
public void testScript3() {
System.out.println("regression");

}
@Test(groups={"regression","smoketesting"})
public void testScript4() {
System.out.println("regression,smoketesting");

}
@Test(groups="smoketesting")
public void testScript5() {
System.out.println("smoketesting");

}
}

testng.xml:

=========

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">

<suite name="Suite" parallel="none">

  <test name="Test">

  <groups>

         <define name="all">

            <include name="regression"/>

            <exclude name="smoketesting"/>

         </define>

         <run>

            <include name="all"/>

         </run>

      </groups>

    <classes>

      <class name="testngdemo.GroupDemo"/>

    </classes>

  </test> <!-- Test -->

</suite> <!-- Suite -->