Running a Java Spring Boot app on a 512 MB VPS with lightweight monitoring

I wanted to see how a fairly representative Java Spring Boot application behaves on a very small VPS, especially the difference between configured heap and actual JVM process memory. The test app uses Spring Boot 3.5.x, Spring MVC, JPA/Hibernate, H2, embedded Tomcat, Actuator, scheduled work, and outbound HTTP. I also kept lightweight monitoring on the same machine. The original 256 MB configuration was too tight. With 512 MB RAM + 256 MB swap , the application completed the test reliably. Full setup and measurements are in the linked article. Since then I’ve also managed to get the same application working on a 256 MB VPS with swap using JDK 25 Compact Object Headers and tighter JVM settings . I’m preparing that as a separate follow-up experiment.