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Using System Properties

There are different parameters which affect the system properties passed to Surefire providers:

systemPropertyVariables

This configuration is the replacement of the deprecated systemProperties. It can accept any expression value referencing Maven's properties that can be converted to a String value or arbitrary literals.

<project>
  [...]
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>3.5.0</version>
        <configuration>
          <systemPropertyVariables>
            <propertyName>propertyValue</propertyName>
            <buildDirectory>${project.build.directory}</buildDirectory>
            [...]
          </systemPropertyVariables>
        </configuration>
      </plugin>
    </plugins>
  </build>
  [...]
</project>

systemPropertiesFile

This configuration allows to add system properties through an external properties file whose path is given via this plugin parameter.

systemProperties (Deprecated)

<project>
  [...]
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>3.5.0</version>
        <configuration>
          <systemProperties>
            <property>
              <name>propertyName</name>
              <value>propertyValue</value>
            </property>
            [...]
          </systemProperties>
        </configuration>
      </plugin>
    </plugins>
  </build>
  [...]
</project>

Take note that only String typed properties can be passed as system properties. Any attempt to pass any other Maven variable type (e.g. a List or a URL variable) will cause the variable expression to be passed literally (unevaluated). So given the example below:

<project>
  [...]
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>3.5.0</version>
        <configuration>
          <systemProperties>
            <property>
              <name>buildDir</name>
              <value>${project.build.outputDirectory}</value>
            </property>
          </systemProperties>
        </configuration>
      </plugin>
    </plugins>
  </build>
  [...]
</project>

The string ${project.build.outputDirectory} will be passed on literally because the type of that expression is a File, not a String.

To inherit the systemProperties collection from the parent configuration, you will need to specify combine.children="append" on the systemProperties node in the child pom:

  <systemProperties combine.children="append">
      <property>
         [...]
      </property>
   </systemProperties>

Effective System Properties

The effective system properties are merged from the following sources:

  1. systemProperties
  2. systemPropertiesFile
  3. systemPropertyVariables
  4. User properties from the current Maven session (if promoteUserPropertiesToSystemProperties is not set to false)

where latter items may overwrite properties with the same name of former items.

Special VM Properties

Some system properties must be set on the command line of the forked VM, and cannot be set after the VM has been started. These properties must be added to the argLine parameter of the Surefire plugin. E.g.,

  <argLine>-Djava.endorsed.dirs=...</argLine>