How to Slash Spring Boot Memory Usage by Over 40% for Local Development

When developing basic Spring Boot applications, memory consumption can become a nightmare, especially when running multiple micro‑services locally. While Spring Boot and the JVM have sensible defaults, adjusting certain configurations can dramatically lower memory usage during development.

Who Consumes Memory

The JVM is the primary consumer, using heap, metaspace, thread stacks, and other areas.

To reduce memory consumption, we need to pass explicit parameters to the JVM.

Preparation

Install Docker and docker‑compose.

Use Java 17 (any version from 8 upwards works, except some old Java 8 patches).

Use Spring Boot.

Configuration File

Create a file named dev.jvm.conf with the following content:

# dev.jvm.conf
# Override application properties
SERVER_TOMCAT_ACCEPT_COUNT=3
SERVER_TOMCAT_MAX_CONNECTIONS=3
SERVER_TOMCAT_THREADS_MAX=3
SERVER_TOMCAT_THREADS_MIN_SPARE=1
SPRING_MAIN_LAZY_INITIALIZATION=true

# JVM options
JAVA_TOOL_OPTIONS=-XX:+UseSerialGC -Xss512k -XX:MaxRAM=200m

Then pass these environment variables to Docker containers via docker‑compose:

# docker-compose.yml
services:
  service1:
    image: service1:dev
    env_file:
      - dev.jvm.conf

  service2:
    image: service2:dev
    env_file:
      - dev.jvm.conf

Run docker-compose up and observe the reduced memory footprint.

Detailed Parameter Explanation

SERVER_TOMCAT_ACCEPT_COUNT : Max queue length for incoming connections when all request‑handling threads are busy (default 100).

SERVER_TOMCAT_MAX_CONNECTIONS : Maximum simultaneous connections Tomcat can handle (default 8192).

SERVER_TOMCAT_THREADS_MAX : Upper limit for Tomcat request‑handling threads (default 200).

SERVER_TOMCAT_THREADS_MIN_SPARE : Minimum spare threads for embedded Tomcat (default 10).

SPRING_MAIN_LAZY_INITIALIZATION : When set to true, all beans are lazily initialized, shortening startup time.

JAVA_TOOL_OPTIONS : -XX:+UseSerialGC: Use a single‑threaded garbage collector. -Xss512k: Limit each thread stack size to 512 KB. -XX:MaxRAM=200m: Cap JVM RAM usage at 200 MB.

Conclusion

By properly configuring the JVM and Spring Boot and understanding where memory is consumed, developers can significantly reduce local memory usage and improve development efficiency.

Original article translated from Medium .