# Change/Set default port for an API

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Published 2022-12-03

In Sprint Boot application the default port is 8080, which generally is good, but sometimes we want to use another port number.

This may be done in several ways:

# by adding in application.properties one line of text :

server.port=8081

# by adding in application.yaml one line of text :

server:
  port : 8081

Info

Specifically, we can create a property file for each environment : application-dev.properties, application-test.properties, application-qa.properties, application-prod.properties.

# using `server.port` argument with the java command

Example:
java -jar target/rest-demo-v1.jar --server.port=8081

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v3.0.1)

2023-01-07T21:30:11.828+02:00  INFO 19268 --- [           main] c.example.restdemo.RestDemoApplication   : Starting RestDemoApplication vv1 using Java 19.0.1 with PID 19268 (D:\GitHub-Projects\Projects\Spring-Boot\APIs\SimpleAPI\rest-demo\target\rest-demo-v1.jar started by Catalin in D:\GitHub-Projects\Projects\Spring-Boot\APIs\SimpleAPI\rest-demo)
2023-01-07T21:30:11.830+02:00  INFO 19268 --- [           main] c.example.restdemo.RestDemoApplication   : No active profile set, falling back to 1 default profile: "default"
2023-01-07T21:30:12.643+02:00  INFO 19268 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8081 (http)
2023-01-07T21:30:12.652+02:00  INFO 19268 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-01-07T21:30:12.653+02:00  INFO 19268 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.4]
2023-01-07T21:30:12.725+02:00  INFO 19268 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-01-07T21:30:12.727+02:00  INFO 19268 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 845 ms
2023-01-07T21:30:13.067+02:00  INFO 19268 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8081 (http) with context path ''
2023-01-07T21:30:13.082+02:00  INFO 19268 --- [           main] c.example.restdemo.RestDemoApplication   : Started RestDemoApplication in 1.613 seconds (process running for 1.956)

# using `Dserver.port` argument with the java command

java -jar -Dserver.port=8083 target/rest-demo-v1.jar

        .   ____          _            __ _ _
        /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
       ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
        \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
        '  |____| .__|_| |_|_| |_\__, | / / / /
        =========|_|==============|___/=/_/_/_/
        :: Spring Boot ::                (v3.0.1)

        2023-01-07T21:32:03.571+02:00  INFO 1924 --- [           main] c.example.restdemo.RestDemoApplication   : Starting RestDemoApplication vv1 using Java 19.0.1 with PID 1924 (D:\GitHub-Projects\Projects\Spring-Boot\APIs\SimpleAPI\rest-demo\target\rest-demo-v1.jar started by Catalin in D:\GitHub-Projects\Projects\Spring-Boot\APIs\SimpleAPI\rest-demo)
        2023-01-07T21:32:03.574+02:00  INFO 1924 --- [           main] c.example.restdemo.RestDemoApplication   : No active profile set, falling back to 1 default profile: "default"
        2023-01-07T21:32:04.388+02:00  INFO 1924 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8083 (http)
        2023-01-07T21:32:04.397+02:00  INFO 1924 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
        2023-01-07T21:32:04.397+02:00  INFO 1924 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.4]
        2023-01-07T21:32:04.465+02:00  INFO 1924 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
        2023-01-07T21:32:04.466+02:00  INFO 1924 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 840 ms
        2023-01-07T21:32:04.788+02:00  INFO 1924 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8083 (http) with context path ''
        2023-01-07T21:32:04.803+02:00  INFO 1924 --- [           main] c.example.restdemo.RestDemoApplication   : Started RestDemoApplication in 1.575 seconds (process running for 1.917)