Hello, I'm a longtime user of this site, but was only really lurking on here with no identity. I decided to make an account to show explain how to fix this issue (at least for me).
How I found the problem?
I was struggling with this issue for quite a while too. When looking at the stack-trace, I noticed that even if I had no code running in my main method (except a System.out.print message) , my message still wouldn't print. I did a bit of digging into it and realised that the referenced library also contained a "main" method. You can find this in here "com.mysql.cj.jdbc.admin.TimezoneDump". Upon finding this, it was obvious that my main method wasn't being run at all.
After realising that this was the issue, the most logical solution I could come up with was run-time configurations. Looking at this I noticed that for some reason, Eclipse had made the TimezoneDump class main run instead of my code.
One of the solutions to fix this is to delete this specific run-time configuration.
The other solution (And easiest) is to simply run your code directly. Personally, I choose the latter because I didn't want to have to click twice every time I ran my code.
I hope this helps you guys, it was a big face-palm for me when I noticed that this was the issue. Thank you for all your contributions towards helping me debug code in the past.