@LocalData decides the directory use in the following way:

1. # /package/class/methodname
2. /package/class

So the data is usable from only one test cases or all test cases (with @LocalData) in a test.

However, it's often the case that one wants to use data from multiple test cases,
but not all test cases.

It's great if one can specify the directory name with @LocalData like

public class Test {
    @Rule public JenkinsRule j = new JenkinsRule();

    @Test
    @LocalData("config1")
    public void config1_test1() throws Exception {...}

    @Test
    @LocalData("config1")
    public void config1_test2() throws Exception {...}

    @Test
    @LocalData("config2")
    public void config2_test1() throws Exception {...}
}