In order to add default JVM options to our Maven mvn command we can define an environment variable MAVEN_OPTS. But we can also create a file jvm.config in the directory .mvn in our project root directory. On each line we define a Java option we want to apply. We can specify JVM options, but also Java system properties we want to apply each time we run the mvn command. This directory and file can be added to our source control so that all users that have access to the repository will use the same JVM options.

The following example defines some Java system properties to change the Maven logging. We also add the JVM option --show-version, so that each time we run mvn we also see the version of Java that is used to run our build. We create the file .mvn/jvm.config and the following content:

-Dorg.slf4j.simpleLogger.showDateTime=true
-Dorg.slf4j.simpleLogger.dateTimeFormat=HH:mm:ss
-Dorg.slf4j.simpleLogger.showThreadName=true
--show-version

Now when we run mvn we see in the output the Java version displayed and each log line has a time and thread name:

$ mvn verify
openjdk 19.0.2 2023-01-17
OpenJDK Runtime Environment Temurin-19.0.2+7 (build 19.0.2+7)
OpenJDK 64-Bit Server VM Temurin-19.0.2+7 (build 19.0.2+7, mixed mode, sharing)
22:12:35 [main] [INFO] Scanning for projects...
...
22:12:39 [main] [INFO] ------------------------------------------------------------------------
22:12:39 [main] [INFO] BUILD SUCCESS
22:12:39 [main] [INFO] ------------------------------------------------------------------------
22:12:39 [main] [INFO] Total time:  3.844 s
22:12:39 [main] [INFO] Finished at: 2023-03-26T22:12:39+02:00
22:12:39 [main] [INFO] ------------------------------------------------------------------------
$

Written with Maven 3.9.1

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