<plugin>
   <groupId>org.apache.maven.plugins</groupId>
   <artifactId>maven-surefire-plugin</artifactId>
   <configuration>
      <runOrder>alphabetical</runOrder>
   </configuration>
</plugin>

<plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-surefire-plugin</artifactId>
      <version>2.17</version>
      <configuration>
        <runOrder>alphabetical</runOrder>
    </configuration>
</plugin>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="Selenium Automation" parallel="false">
    <test name="Test1">
        <classes>
            <class name="some.package.Class1"/>
            <class name="some.package.Class2"/>
            <class name="some.package.Class3"/>
        </classes>
    </test>
</suite>

<profile>
    <id>any id</id>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>2.12.4</version>
        <configuration>
            <suiteXmlFiles>
                <suiteXmlFile>src/test/resources/testng.xml</suiteXmlFile>
            </suiteXmlFiles>
        </configuration>
    </plugin/>
</profile>

public static void main(String[] args)
{
    List<Class> testCases = new ArrayList<Class>();

    //Add test cases
    testCases.add(Class1.class);
    testCases.add(Class2.class);
    for (Class testCase : testCases)
           {
                runTestCase(testCase);
           }
}

private static void runTestCase(Class testCase)
{
    Result result = JUnitCore.runClasses(testCase);
    for (Failure failure : result.getFailures())
    {
        System.out.println(failure.toString());
    }
}

import org.junit.runner.RunWith;
import org.junit.runners.Suite;
import org.junit.runners.Suite.SuiteClasses;

@RunWith(Suite.class)
@SuiteClasses({
Test1.class
Test2.class
Test3.class
Test4.class
})

public class TestSuite {

}