maven "cannot find symbol" message unhelpful

update to 3.1 :

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.1</version>
    <configuration>
        <source>1.7</source>
        <target>1.7</target>
    </configuration>
</plugin>

This is a bug in the Maven compiler plugin, related to JDK7 I think. Works fine with JDK6.