Spring boot is an excellent framework and it is well suited for Cloud Run. The startup time of Spring boot application can be well managed and it can run with very little resources.

Check out this guide to deploying spring boot apps on cloud run.

Resources:

Cloud Run documentation for Java applications: https://cloud.google.com/run/docs/tips/java
Spring Boot on Cloud Run example: https://spring-gcp.saturnism.me/getting-started/helloworld/cloud-run
Quickstart: Deploy a Java service to Cloud Run: https://cloud.google.com/run/docs/quickstarts/build-and-deploy/deploy-java-service