Starting a project with debug is slower than normal startup, which is what I found on the Internet. Just delete all breakpoints.
This problem may be caused by the interaction between eclipse and tomcat. When starting tomcat in debug mode, a file read error occurs, and eclipse automatically sets a breakpoint, which causes tomcat to fail to start normally. The solution is as follows: start tomcat in debug mode, open breakpoints veiw, right-click -> Remove all, restart tomcat and it will be OK.