A Testcontainers test using a MySQL container fails with an 'OutOfMemoryError' after running for a while. What is a likely cause and how can it be addressed?
Java interview question for Advanced practice.
Answer
The MySQL container is consuming too much memory on the host. Resource limits should be applied to the container.
Explanation
The most probable cause of an OutOfMemoryError originating from the test process is that the Docker container is consuming excessive memory on the host machine, leaving too little for the JVM. This is especially common with resource-intensive services like databases. The most direct solution is to constrain the container's resource usage. Corrected Code: java @Container private static final MySQLContainer<? mysql = new MySQLContainer<("mysql:8") .withCreateContainerCmdModifier(cmd - cmd.getHostConfig().withMemory(512 1024 1024L)); // 512MB limit