In high school and college I studied basic Java SE. Now moving into enterprise as an adult, I am a bit lost in terms of gaps of knowledge. I am struggling with determining when a java SE program bleeds over into java EE. Is it specifically when I start using a framework for inversion of control like Spring or Quarkus? Where is the line between SE and EE, is it the web server Tomcat or Wildfly that makes an application go from SE to EE?

I coded some fun server apps in Java SE that used websockets -- is this java SE or EE? Is a command line Java program with a listener responding to REST requests still a java SE program?