Play framework depency injection not working

I have tried dependency injection example from here https://dzone.com/articles/guicing-play-framework

public class TestController extends Controller{
@Inject
private Testing test;

public Result result() {
    test.tt();
    return ok();
} 
}

Service Interface code:

public interface Testing {

public String tt();
}

ServiceImpl code:

public class Testingimpl implements Testing{
@Override
public String tt() {
    return "test";
}
}