Cleaned up a slew of Javadoc errors in preparation for switch over to Java 8.
diff --git a/tools/package/bin/onos-service b/tools/package/bin/onos-service
index 299cb9a..9250d5b 100755
--- a/tools/package/bin/onos-service
+++ b/tools/package/bin/onos-service
@@ -4,7 +4,7 @@
 # -----------------------------------------------------------------------------
 
 export JAVA_HOME=${JAVA_HOME:-/usr/lib/jvm/java-7-openjdk-amd64/}
-export JAVA_OPTS="-Xms256M -Xmx2048M"
+export JAVA_OPTS="${JAVA_OPTS:--Xms256M -Xmx2048M}"
 
 cd /opt/onos
 /opt/onos/apache-karaf-$KARAF_VERSION/bin/karaf "$@"