java -javaagent:lombok.jar=ECJ -jar ecj.jar -cp lombok.jar -source 1.8 (rest of arguments)
You may have to add the following VM argument, if you're using an older version of lombok or java:
-Xbootclasspath/p:lombok.jar
If you're using a tool based on ecj, adding these VM arguments and adding lombok.jar to the classpath should work.
It is possible to configure maven-compiler-plugin with maven-dependency-plugin and plexus-compiler-eclipse.
Before the compile phase, you will have to set your MAVEN_OPTS environment variable to include the javaagent argument.
In the example below, target is your ${project.build.directory}.
Use the following commands in sequence to enable lombok with ecj in your Maven build:
mvn clean dependency:copy@get-lombok set MAVEN_OPTS=-javaagent:target/lombok.jar=ECJ (or your OS's equivalent) mvn install set MAVEN_OPTS= (or your OS's equivalent)