Firstly, it was on Sunday. Raises immediate questions about the company's culture. Why is this happening on Sunday? Is this normal? Does it indicate poor planning, desperation, or a toxic work-life balance? Secondly, the interviewer was not a Java developer. A major red flag about the role/team structure. Why is a non-Java developer conducting a core technical interview for a Java role? Poor resourcing, lack of technical leadership, or misunderstanding of the role's needs.