What is more profitable - built-in Tomcat or a separate one?

Question

Java

Just started learning about Spring, specifically the Spring-boot framework. Due to insufficient depth of knowledge, I can’t imagine the mechanics of the container. I pack embedded tomcat into an executable jar and run it on the server. It turns out that on the server (Ubuntu 16.04) several copies of tomcat are spinning - according to the number of running applications. Very resource-intensive, in particular in terms of memory consumption.
If you pack in war and deploy several applications on standalone tomcat, will there be a gain in resource consumption, all other things being equal? Will one tomcat instance serving several applications work in this case, or will several copies still actually run?

Answer 1

You make a typical beginner's mistake, instead of learning spring, you start to wonder
- "What is more profitable <here is some abstract question that needs to be resolved already in a combat project>".
In general, this is such a variant of the manifestation of procrastination.
Do you currently have a memory deficit when deploying? If yes, then buy more memory, it costs a penny or do not run many instances of the application and continue to learn spring.
If not, then continue to learn the spring.
PS There is a difference, and it is in favor of one Tomkat for several applications. But the difference is negligible. Using embedded servlet containers is more beneficial in terms of micro-service architecture. But you don't need it now.