KCOM Group Java Developer interview questions

Got the hiring process started via a recruiter. The initial interview was with HR for a phone screening. It was very pleasant and standard as far as phone screenings go. After that, I was given a programming assignment to work on. I completed the assignment, handed it in within the allotted time, and then received a negative response without any sensible feedback. The only feedback was, "there are broad issues with the code". I went back to my code to check it and the solution does work and I cannot see any glaring issues, so I will never know what these "broad issues" were. After spending time and effort from my side, the least one would expect was some useful feedback regardless of the outcome.