The lecture content is... good. It's a bit vague to approach JSP for the first time, and it's good to organize theoretical details after learning it elsewhere. However, it's extremely difficult to listen to and see the good content. First of all, as many people have pointed out, the sound is really hard to hear until the end. Even if you turn up the volume to the max and block all other applications for fear of damaging your hearing due to KakaoTalk for PC or other computer sound effects, and then only listen to this lecture, you still can't hear important content well, and not only is the volume low, but the pronunciation is also muffled, so it's often hard to find what was said. And you can't see the text. Even if you set the resolution of the lecture video to the max and watch it in full screen, the text itself is often broken because it was filmed in low resolution and small text, so the source code is often not clearly visible. If you can't see the text, if you can hear the voice well, you can infer one of the two, but in many cases, both are broken. There have been more than a few times when I couldn't see a single letter, so I paused the video every 0.1 seconds and desperately searched for a frame where the letter was a little less broken. And lastly... I don't know if it's because the lecture is not for beginners but for those who already know JSP and covers theoretical elements that need to be briefly explained... but there are so many cases where the content that needs to be explained is hastily processed in less than a second with shortcut keys (without even showing what was entered) and then skipped over. Many of the reviews below point out that errors appear when you input and run the same code, but in my opinion, they don't show you all the source code that needs to be entered, and after pressing the auto-complete and auto-import shortcut keys, they say that the original coding is to copy and paste from somewhere else to increase accuracy, and so they skip over it all, saying, "I'm giving a lecture, so I'll show you this much. This isn't how you spend your time." So I think the problem occurs because you can't see the entire code that you entered. In particular, in the servlet file related to cookies or sessions, "import javax.servlet.http.Cookie;" "There are many cases where the same declaration syntax needs to be added to the top, but auto-completion doesn't work, so I often just hastily use a shortcut key to auto-import and then say 'Oh, that's it~' and that's it. (What happened? ㅜㅜ) No matter how slowly I play the video, I have to find each frame and check it with difficulty while freezing the screen every 0.1 seconds because I've been hastily using a shortcut key so that I can never see what letters were entered. I didn't want to write a negative review for a lecture that was almost free. Until last week, I just gave it four or five stars and wrote 'Thank you~' and tried to forget about it. However, if a personal YouTuber's lecture is like this, I can just avoid that person's lecture in the future, but since the provider's name is Inflearn Original, I can't avoid worrying about whether other Inflearn Original paid lectures will be like this in the future. These days, Wadiz has an Infren Original web programming package. Since it's web programming, what if the same person teaches all the lectures? Even for that paid lecture, even if you close KakaoTalk and all other applications and turn up the volume to the max, you can't hear the sound, so you have to repeat it several times to guess the content. Even for that paid lecture, the source code that appears on the screen is so small that it's all broken, so you have to freeze the screen every 0.1 seconds to desperately find a frame with even one less broken letter. I can't help but worry that I've wasted my money after paying in advance... Anyway, the lecture isn't bad. It's okay to organize after attending other lectures.