When I did the initial display of the screen using Spring Framework, index.jsp was inevitably referenced. I will write it as a memorandum because I fell into a situation where the intended screen is not displayed.
I first suspected Controller. However, I thought that it was not a Controller because the initial display "/" was set in the value of @RequestMapping.
Next, I suspected web.xml, but there was no description that specifically referred to index.jsp.
Finally, I checked the web.xml of Tomcat. The welcome file was specified there.
It was improved by overwriting this description with web.xml on the project side.
When you fall into such a case, first check the web.xml referenced by tomcat. ..