Let me tell you something about my study experience. In the first two years, I learned JAVA only by reading books and practicing examples in books, but the effect has not been good. Later, because the project needed to be formally developed in JAVA, I found that I had forgotten everything I had practiced before, so I had to pick up the book and read it again. Which means it's basically useless. Now I think about it, because most of them are plagiarized, so I don't think much, so I don't know why. So I strongly suggest that you set an imaginary project goal for yourself when you study, and do something, whether it's a web page or an application, so that you can learn quickly. After you have a certain feeling about java, you are reading its documentation and source code. I suggest you start with the lower version of JAVA source code, because it has few classes and looks easy to understand. Then you will know that what you used to code is naive, and you can get it in one or two sentences. If you feel a little better, you can also consider some training if appropriate. After all, it is easier than self-study. In addition, we can learn from other people's experience, such as "Power Node" or "Wang Yong Java". Some students responded well. I suggest you learn more about other training institutions. Y.