Executing multiple test sequentially with different parameters testng

Question

I was trying to run multiple test with different parameters sequentially using data providers, basically the scenario is suppose there are 5 test completing a test flow and

Answer 1

So my concern is that all test should run first with first parameter air and then again all test should execute with next parameter "earth"

Here is the output that i got for the input "air" and "earth"

Test-1 with data: Air
Test-2 with data: Air
Test-1 with data: Water
Test-2 with data: Water

Test Class - RandomTest

public class RandomTest {
    private String str = "";

    public RandomTest(String str) {
    this.str = str;
    }

    @Test
    public void firstTest() {
    System.out.println("Test-1 with data: "+str);
    }

    @Test
    public void secondTest() {
    System.out.println("Test-2 with data: "+str);
}}

Factory class - SampleFactory

public class SampleFactory {
@Factory(dataProvider="dp")
public Object[] createInstances(String str) {
    return new Object[] {new RandomTest(str)};
}

@DataProvider(name="dp")
public static Object[][] createData() {
    return new Object[][] {
            new Object[] { new String("Air") },
            new Object[] { new String("Water") }
    };
}}

Run the class SampleFactory from testng.xml, Please note: group-by-instances="true"

Ref: http://testng.org/doc/documentation-main.html#factories
Ref: http://java.dzone.com/articles/testng-run-tests-sequentially