Currently, I feel that my Java skills are quite good, but I’m not sure what level I’m at. How can I determine my current level? What do I need to know to confidently say that I am proficient in Java backend development? Additionally, could you please suggest some technologies and libraries commonly used in backend development? I am eager to learn more and improve my skills.

I have been working on several Java backend projects and have tried to follow best practices and design patterns. I expected to gain a clear understanding of my proficiency level, but I am still unsure where I stand. I am looking for advice on how to accurately assess my skills and what specific areas I should focus on to improve further.