When creating a Spring Boot application, in development environment, IntelliJ Idea creates a Run Configuration that is without Maven and it directly calls the static Main method with type of 'Spring Boot'.
When I run without Maven my JSP template files are not being resolved and I get the error page below.
When I run with Maven they are resolved but I can't debug. I am seeing some POM.xml configuration to be able to attach the debugger but then it debugs all the time even when I fire the app with Run and not Debug.
Should I run Boot app without Maven at all?
If I shouldn't, is this how the debug should be?
I feel something is wrong here...
Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.
Thu Mar 16 08:53:54 GMT 2017
There was an unexpected error (type=Not Found, status=404).
No message available
I believe I see this error page because it tries to locate my index.jsp, can't find it, then tries for error.jsp and can't find that as well.
Okay after doing more research it seems it is right to run Spring Boot application through the Main method directly rather than Maven in development environment.
Issue with JSPs are not being rendered without Maven was the Tomcat Jasper dependency's scope was <scope>provided</scope>, after changing that to "compiled" or "runtime" it started to work without maven. Interestingly when it was "provided" JSP rendering was only working with Maven.
You can try different URLs like URL without or with the project (artifact) name. Maybe something wrong with the way how IDEA and maven deploy your war. Also, it is possible to run the app from maven and then connect with the Remote run configuration of the IDEA to it. For this, you need to use mvnDebug instead of mvn - it is situated in the same folder as mvn ($MAVEN_HOME/bin/). And then you need to add Remote configuration to the IDEA with the port 8000 - it is default port.
Try re-importing Maven projects first before running application from IntelliJ, or make it happen automatically when you change something in your pom.xml file (File | Settings | Build, Execution, Deployment | Build Tools | Maven | Importing | Import Maven projects automatically).
I use IntelliJ execution in my dev environment. What's more, if you would like to have features like hot-reloading for instance, consider using devtools module shipped with Spring Boot which easily integrates with IntelliJ debug execution (just add spring-boot-devtools to your dependencies).