What question in an interview do you prefer not to answer or feel less confident about?

Most often, they feel less confident when it comes to questions related to the deep internal implementation of the JVM, such as how the garbage collector works at a low level or the intricacies of the JIT compiler. Questions on complex aspects of multithreading, such as working with volatile, happens-before, or lock-free algorithms, can also be challenging.

It is important to honestly admit if a topic is not sufficiently studied and to show a willingness to learn and understand complex issues.