JaCoCo

Prepares a property pointing to the JaCoCo runtime agent that can be passed as a VM argument to the application under test. Depending on the project packaging type by default a property with the following name is set:

If your project already defines VM arguments for test execution, be sure that they will include property defined by JaCoCo.

One of the ways to do this in case of maven-surefire-plugin - is to use syntax for late property evaluation :

You can define empty property to avoid JVM startup error Could not find or load main class @{argLine} when using late property evaluation and jacoco-maven-plugin not executed.

Another way is to define "argLine" as a Maven property rather than as part of the configuration of maven-surefire-plugin:

Resulting coverage information is collected during execution and by default written to a file when the process terminates.