Looping through an Array---Partial Solution

Watch OUT!!! There are still some missing parts!!
class ArrayTest {

    String[] firstNames = { "Dennis", "Grace", "Bjarne", "James" };
    String[] lastNames = new String[firstNames.length];

    void printNames() {
       for(i=0; i <firstNames.length; i++)
           System.out.println(firstNames[i] + );
    }

    public static void main (String arguments[]) {
        ArrayTest a = new ArrayTest();
        a.printNames();
        System.out.println("-----");
        a.lastNames[0] = "Ritchie";
        a.lastNames[1] = "Hopper";
        a.lastNames[2] = "Stroustrup";
        a.lastNames[3] = "Gosling";
        a.printNames();
    }
}