I am new learner of Ratpack, can anyone explain what is difference between Ratpack and tomcat or other server same like tomcat, and can we use Ratpack for large scope applications, Ratpack is secure or not? please help.
Ratpack is built on Netty (a non-blocking, embedded server).
It is no-more inherently secure (or not secure) than Tomcat. Tomcat probably has more developers looking at it but it also has a LOT more code where bugs can hide. In my experience most projects are more likely to suffer security issues from defects in their application code than the frameworks they use.