I haven't published it in any public repository, but feel free to use it all the same.
Attaches itself to the validate stage (before compiling).
Example usage:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>es.ingbank.qa</groupId>
<artifactId>test</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<plugins>
<plugin>
<groupId>es.ingbank.qa</groupId>
<artifactId>filediff-maven-plugin</artifactId>
<version>1.0-SNAPSHOT</version>
<configuration>
<oldFile>original.java</oldFile>
<newFile>new.java</newFile>
<showDiff>true</showDiff>
<abortOnDiff>true</abortOnDiff>
</configuration>
<executions>
<execution>
<goals>
<goal>diff</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>