Profiles

Profiles provide the if-else of the POM. It is basically aimed towards configuring your build depending on the properties. A couple of the usual properties used are the JDK, the OS ( Operating System ). Furthermore, Profiles can be activated depending on whether a particular file exists or not.

Generic Property Activation

You can activate a profile when a specific system property is set.  Note only properties set on the Maven command line can activate profiles.  Properties set in the POM, the parent POM, or other profiles have no effect.

To activate a profile when a certain property has a certain value (in this case myproperty=myvalue):

<profiles>
  <profile>
    <activation>
      <property>
        <name>myproperty</name>
        <value>myvalue</value>
      </property>
    </activation>
    ...
  </profile>
  ...
</profiles>

To activate a profile when a certain property exists (regardless of value):

<profiles>
  <profile>
    <activation>
      <property>
        <name>myproperty</name>
      </property>
    </activation>
    ...
  </profile>
  ...
</profiles>

JDK Activation

OS Activation

To configure the activation via the operating system, you can specify at least one out of four (4) things - name, family, architecture, and version.

The Profile OS Activation part looks like this

<profiles>
  <profile>
    <activation>
      <os>
        <name>windows xp</name>
        <family>windows</family>
        <arch>x86</arch>
        <version>5.1</version>
      </os>
    </activation>
    ...
  </profile>
  ...
</profiles>

For the family, architecture, and version, this is checked by comparing these values against System.getProperties( "os.name" ), System.getProperties( "os.arch" ), System.getProperties( "os.version" ) respectively. Thus, the allowed values for these tags depends on what are allowed in those System properties.

However, for the family, there is a list of possible family values you can enter.

Warning You may need to declare your os family, name, arch, and version all in small caps ( see MNG-2814 ).

File Activation 

To activate when a certaint file exists:

<profiles>
  <profile>
    <activation>
      <file>
        <exists>myfile</exists>
      </file>
    </activation>
    ...
  </profile>
  ...
</profiles>

To activate when a certaint file does not exist:

<profiles>
  <profile>
    <activation>
      <missing>
        <exists>myfile</exists>
      </missing>
    </activation>
    ...
  </profile>
  ...
</profiles>

The definition of the path does not support use of properties, settings or environment variables for Maven 2.0.4. Do not try anything of the form <exists>${user.home}/.m2/com/oracle/ojdbc</exists> instead you will need to hard code the complete path.

Others

Negation

Prepend "!" on property name, os family, os name, os version and os arch to negate.

Meaning

<profiles>
  <profile>
    <activation>
      <property>
        <name>!myproperty</name>
      </property>
    </activation>
    ...
  </profile>
  ...
</profiles>

gets executed when myproperty is not defined. And

<profiles>
  <profile>
    <activation>
      <os>
        <name>!windows xp</name>
        <family>!windows</family>
        <arch>!x86</arch>
        <version>!5.1</version>
      </os>
    </activation>
    ...
  </profile>
  ...
</profiles>

gets evaluated as true when

name != "windows xp" AND family != "windows" AND arch != "x86" AND version != 5.1

Active by Default 

Set to true to activate  by default