Go to $ORACLE10_HOME/bin
and create the file oc4j-jrebel.sh
with the following contents:
#!/bin/bash export OC4J_JVM_ARGS="-javaagent:$AGENT_PATH_UNIX $OC4J_JVM_ARGS" `dirname $0`/oc4j $@
Use this script instead of oc4j
if you want to run OC4J with JRebel.