output.txt

$ java Test
v2

Test.java

public class Test {
    public static void main(String[] args) {
        VisTest v1 = new VisTest("v1");
        VisTest v2 = new VisTest("v2");

        v1.doIt(v2);
    }
}

VisTest.java

public class VisTest {
    private String foo;

    public VisTest(String foo) {
      this.foo = foo;
    }

    public void doIt(VisTest other) {
        System.out.println(other.foo);
    }
}