FindBugs fails on timeout

See SONAR-1439. Findbugs fails with the following logs :

[java] Timeout: killed the sub-process
...
[Fatal Error] :-1:-1: Premature end of file.

Add the findbugs-maven-plugin to the plugins section of the pom and configure the parameter timeout.

My project only builds with JDK 1.4

As SonarQubecan only run with JDK1.6 or higher, some configuration should be added to the pom.xml to indicate that the project requires JDK1.4:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <source>1.4</source>
        <target>1.4</target>
    </configuration>
</plugin>