The [documentation](https://logging.apache.org/log4j/transform/log4j-transform-maven-plugin.html#process-classes-required-parameters) references two required plugin parameters: `<sourceDirectory>` and `<sourceDirectory>` (which are the same). It seems the second one should be `<outputDirectory>`, according to `LocationMojo`'s code: https://github.com/apache/logging-log4j-transform/blob/main/log4j-transform-maven-plugin/src/main/java/org/apache/logging/log4j/transform/maven/LocationMojo.java#L83 I believe this is the line that needs to be fixed: https://github.com/apache/logging-log4j-transform/blob/main/src/site/antora/modules/ROOT/pages/log4j-transform-maven-plugin.adoc?plain=1#L212