Yes, there are a lot of questions about threads. But the questions are not so tough as what people thought. In fact, most questions in the mocks, including JQ+, are much difficult than the real
test. I lost 1 in this field. But I think the reason is that the question itself is ambiguous.
If you want to take the mocks, I suggest you to take the JQ+. In JQ+, the GUI is not so friendly, but the questions are valuable.