This Java article explains what is the use of mvnw and mvnw.cmd files in the Spring Boot application.
These files present in the root directory of Spring Boot application are from Maven Wrapper.
The Maven Wrapper is an easy way to ensure a user of your Maven build has everything necessary to run your Maven build.
This allows you to run the Maven project without having Maven installed and present on the path. It downloads the correct Maven version if it’s not found.
mvnw is executable shell script (for Unix / Linux) and command to execute it is ./mvnw clean install
mvnw.cmd is executable batch file (for Windows) and command to execute it is mvnw.cmd clean install