Schibsted Java Developer interview questions

I was contacted by email from an internal recruiter. Then we scheduled the time for the screening interview with him and was ok. During the interview he asked me many things about my CV. The conversation lasted more than 30 min. Then he asked me to develope a java test program as second step of the interview process. I made a good test exercise, but after 10 days he responded they they didn't like and the process stopped like this I have never understood what was wrong with my code. As they didn't technically explained anything or some tech reason.