Passing parameters into springboot application

• User OS env variable
• Use java -Dk1=v1 -Dk2=v2
• Program argument java -jar my.jar --k1=v1 --k2=v2
• Use an external application.properties file and pointing to it with export spring.config.location=/tmp/application.properties or passing it in with java parameter -Dspring.config.location=/tmp/application.properties