How To Provide Explicit Mapping In Spring Boot Project Normally Whenever we configure and start our first spring boot project and check in localhost:8080 it will display Whitelabel Error Page because there is no explicit mapping found , Today we will learn how to provide an explicit mapping. Open your IntelliJ IDE & go to your project Right Click on your project and select the new package as shown below Give package name as the controller After that Right Click on the package and select new java class and named as HelloMessage After That Write The controller code as shown below After that restart the server and open browser and type localhost:8080 Enjoy Explicit Mapping !!!!!