How to configure port for a Spring Boot application

In this tutorial we are going to learn about configuring the port number for a Spring Boot application.

when we generate a Spring Boot project using Spring Initializr or Spring tool suite IDE a file named application.properties is also generated by default with the project under src/main/resources directory.

As said set server.port as system property using command line option to jvm -Dserver.port=8090 or add application.properties in /src/main/resources/ with

server.port=8090

For random port use

server.port=0

Similarly we can also add application.yml in /src/main/resources/ with

server:
  port : 8090

Imagine a scenario where you have application.properties , application.yml files under /src/main/resources/ and youre also passing the port no as a command line argument to a spring boot application that you want to run.

In the above scenario which port no is considered by the spring boot application?

Firstly the port no passed as a command line argument is given high priority since this is happening at the runtime and then follewed by application.properties and application.yml.