Where the binnary of mvn knows which mojo do i want to execute?

I am novice using mvn and having a look to /usr/bin/mvn, I can see the eval
method, but I can not understand where the mojo is called.
Please can anyone explain how the eval method works?
I would be very pleased if someone could help me.

////////////////////That is my eval
method/////////////////////////////////////

eval "${JAVACMD}" \
${MAVEN_OPTS} \
-classpath "${CLASSWORLDS_JAR}" \
"-Dclassworlds.conf=${M2_HOME}/bin/m2.conf" \
"-Dmaven.home=${M2_HOME}" \
"-Dos.arch=`uname -m`" \
${CLASSWORLDS_LAUNCHER} $(${QUIET_FLAG} & echo \-q) $(${OFFLINE_FLAG} &
echo \-o) ${QUOTED_ARGS} ${MAVEN_ARGS}