If you terminate a running Spring boot application from within the eclipse, at times the port on which embedded tomcat listens does not free up. I found the below commands on one of the StackOverflow posts which are really handy.
C:\yourdir>netstat -aon |find /i “listening” |find “8080”
TCP 0.0.0.0:8080 0.0.0.0:0 LISTENING 68
Now grab the PID (68 in this case) and run the below command to kill it.
C:\yourdir>taskkill /F /PID 68