As per request attached to comment on changes needed to OS X installer.

When running from the command line (as opposed to instantiating a JVM programmatically), Java 7 or Java 8 on OS X has a dependency on the very old Java 6 installation for OS X, available at http://support.apple.com/kb/DL1572. When the user installs the Java 6 package from Apple, /usr/bin/java points to the Java 6 installation. Oracle Java installs into /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home. To run a Java 8 JVM from the command line, the user needs to give the full path to the "java" executable – /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java.

The quick fix is to change the /Library/Application Support/Jenkins/jenkins-runner.sh file with the following unified diff:

— jenkins-runner.sh 2015-05-16 16:22:42.000000000 -0400
+++ /Library/Application Support/Jenkins/jenkins-runner.sh 2015-04-06 22:20:02.000000000 -0400
@@ -26,6 +26,8 @@

home=`$defaults JENKINS_HOME` && export JENKINS_HOME="$home"

+export JAVA_HOME="/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/"
+
add_to_args() {
val=`$defaults $1` && args="$args --${1}=${val}"
}
@@ -41,5 +43,7 @@

echo "JENKINS_HOME=$JENKINS_HOME"
echo "Jenkins command line for execution:"
-echo /usr/bin/java $javaArgs -jar "$war" $args
-exec /usr/bin/java $javaArgs -jar "$war" $args
+# echo /usr/bin/java $javaArgs -jar "$war" $args
+# exec /usr/bin/java $javaArgs -jar "$war" $args
+echo "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java" $javaArgs -jar "$war" $args
+exec "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java" $javaArgs -jar "$war" $args

NOTE: I didn't see the comment addition until this past week. Sorry for the delay.