How to Change Spring Boot Default Port?

The Spring Boot framework provides the default embedded server (Tomcat) to run the Spring Boot application. It runs on port 8080. It is possible to change the port in Spring Boot.

If you want to change the default port you have several options. But using application.properties option is recommended to overwrite default values.

To override the default port, we need to specify server.port property in application.properties file.

Changing Default Port in Spring Boot

In the application.properties file, we can set a custom port number for the property server.port

server.port = 9090

In the application.yml file, you can find as follows −

server: 
    port: 9090

Running Spring Boot in Random Port

In the application.properties file, we can set a random port number for the property server.port

server.port = 0

In the application.yml file, you can find it as follows −

server: 
   port: 0

Note − If the server.port number is 0 while starting the Spring Boot application, Tomcat uses the random port number based on the availability.

Using Command-Line Arguments

We can also set the server port using the java command line argument as follows.

java -jar spring-boot-app.jar --server.port=8009

or by using the equivalent syntax:

java -jar -Dserver.port=8009 spring-boot-app.jar