We need our data persistence with configuring our datasouce:

In application.properties:

spring.h2.console.enabled=true
spring.h2.console.path=/h2

spring.datasource.url=jdbc:h2:file:~/gs-spring-boot
spring.datasource.username=sa
spring.datasource.password=
spring.datasource.driver-class-name=org.h2.Driver
 

spring.datasource.max-active=10
spring.datasource.max-idl=8
spring.datasource.max-wait=10000
spring.datasource.min-evictable-idle-time-millis=1000
spring.datasource.min-idle=8
spring.datasource.time-between-eviction-runs-millis=1

"

spring.datasource.url=jdbc:h2:file:~/gs-spring-boot

" tells to save the in memory data into a file called ‘gs-spring-boot‘, you can name the file whatever you want.

Rebuild the application, login h2:

Make sure you change the JDBC URL. Now everytime you restart the server, data won‘t lost

[Spring boot] Configuring and Accessing a Data Source