# JVM (Spring Boot / Scala / Kotlin)

## Startup delay

Spring Boot loads the full application context before accepting HTTP. Cold starts typically take 60–120 seconds depending on the number of beans and auto-configuration classes.

```yaml
livenessProbe:
  tcpSocket:
    port: 8080
  initialDelaySeconds: 120
  periodSeconds: 30
  failureThreshold: 6
readinessProbe:
  httpGet:
    path: /actuator/health
    port: 8080
  initialDelaySeconds: 90
  periodSeconds: 15
  failureThreshold: 3
```

If the app exposes a Spring Actuator health endpoint, prefer it for readiness over the root path.

## Heap limit

Set `-Xmx` to keep the heap within the container memory limit. The JVM does not automatically respect cgroup limits on older JDK versions.

```yaml
env:
  - name: JAVA_OPTS
    value: "-Xmx512m -Xms256m"
resources:
  limits:
    memory: 768Mi
  requests:
    memory: 512Mi
```

Keep `-Xmx` 25–33% below the container limit to leave room for off-heap memory (metaspace, direct buffers, GC overhead).

## Resources

512Mi–1Gi request is typical. JVM startup can spike higher — use `requests` to reserve and `limits` to cap.