Question

Inside a maven project with some resources configured like this :

<webResources>
    ....
    <resource>
        <directory>${project.build.directory}/${temp.dir}</directory>
    </resource>
</webResources>

the ${temp.dir} is generated conditionally by a plugin and do not exists always. When it is not there maven of course fail with an NPE, how could I fix this ?

Answer 1

I’m not sure if I understand what your problem (exactly) is, but it seems to me that Maven profiles could help you:

http://maven.apache.org/guides/introduction/introduction-to-profiles.html

In your case, probably you need profile activation on property existence, like this:

<profiles>
  <profile>
    <activation>
      <property>
        <name>temp.dir</name>
      </property>
    </activation>
    ...
  </profile>
</profiles>