To generate the jar, just run maven real quick. # Base java:8 FROM java:8 # Add jar to container ADD /target/example*.jar javaopts.jar # Entry in json format ENTRYPOINT

Since the jar will be built in the target folder we grab it from there and place a renamed copy into the container.

The first thing we’ll do is setup a basic Dockerfile similar to the one in the Spring Boot guide. Now that we have a baseline, let’s move onto the Docker stage. Running this app in IntelliJ with no memory settings will show some basic output with memory settings: = Memory Info = Free memory: 221 MB Allocated memory: 245 MB Max memory: 3,641 MB Total free memory: 3,617 MB =Ĭhanging the memory values to -Xmx3g -Xms3g we get a different output: = Memory Info = Free memory: 2,713 MB Allocated memory: 2,944 MB Max memory: 2,944 MB Total free memory: 2,713 MB = Looking at the sample code, we have a basic pom file that imports Spring Boot dependencies: 4.0.0 vc.c4.javaopts example-javaopts 0.0.1-SNAPSHOT Spring Boot Tomcat JAVA_OPTS Spring Boot Tomcat JAVA_OPTS Example 1.7 $

Looking at the sample code, we have a basic pom file that imports Spring Boot dependencies: I’ve created this repo as a test case and you can refer back to it when needed. After some testing, I found this to be incorrect when running a Spring Boot jar in a Docker container, I’ll explain why and give a solution in this post.īefore I start, let’s setu p a basic test environment that prints out the current memory setup so we can test in various situations. JAVA_OPTS comes from the Tomcat/Catalina world and when searching for “Docker and javaopts” on Google you’ll find many references to just adding JAVA_OPTS to the Docker environment. While adjusting some environment variables recently, I came across an odd issue with Docker, Spring Boot and JAVA_OPTS.

Java_opts environment variable