(The main purpose of this group of interview questions is to help those friends who do not have practical experience in Java software development but are trying to find Java software development work to better win the written examination and interview in the written examination. Because the scope of this group of interview questions is very wide, wide and complex, you can't read and learn this group of interview questions in oneortwo days. Even if you have learned the relevant skills, at least you can spend a month digesting and mastering this interview book. Therefore, we should make preparations early. From the day you get this interview book, you must study a few questions in your spare time every day, Over time, when you go out to face J, everything will come naturally, and you will naturally feel comfortable facing J.)