When setting PARAM_RUNTIME option to JRE location inside JDK (something like /path/to/JDK_ROOT/Contents/Home/jre), bundling would fail with ConfigException:
com.oracle.tools.packager.ConfigException: Java Runtime does not include [Contents/Home/jre/lib/[^/]+/libjvm.dylib, Contents/Home/jre/lib/rt.jar]

{runtime=RelativeFileSet{basedir:/Library/Java/JavaVirtualMachines/jdk1.8.0_40.jdk/Contents/Home/jre, files:[lib/libsaproc.dylib, lib/fonts/LucidaBrightItalic.ttf, lib/fonts/LucidaBrightDemiBold.ttf, lib/libprism_es2.dylib, lib/libjavafx_font_t2k.dylib, lib/management/management.properties, bin/tnameserv, lib/libunpack.dylib, lib/images/cursors/motif_LinkDrop32x32.gif, lib/jfr/profile.jfc, lib/images/cursors/motif_CopyNoDrop32x32.gif, lib/javaws.jar, lib/currency.data, lib/ext/sunec.jar, lib/security/java.policy, lib/content-types.properties, bin/rmid, lib/libjava_crw_demo.dylib, lib/libattach.dylib, lib/fontconfig.properties.src, lib/cmm/PYCC.pf, README, lib/ext/cldrdata.jar, lib/plugin.jar, lib/sound.properties, lib/fonts/LucidaTypewriterRegular.ttf, lib/libprism_common.dylib, lib/libjfr.dylib, lib/security/blacklist, lib/libglib-lite.dylib, lib/libjsdt.dylib, lib/libjsound.dylib, lib/jvm.hprof.txt, lib/server/Xusage.txt, lib/libhprof.dylib, lib/fonts/LucidaBrightRegular.ttf, lib/libjpeg.dylib, lib/libawt.dylib, lib/libsplashscreen.dylib, lib/images/cursors/motif_MoveDrop32x32.gif, lib/security/US_export_policy.jar, bin/orbd, lib/jfr.jar, lib/security/local_policy.jar, lib/psfont.properties.ja, lib/ext/dnsns.jar, THIRDPARTYLICENSEREADME.txt, lib/fonts/fonts.dir, lib/libkcms.dylib, lib/libnio.dylib, lib/ext/localedata.jar, lib/javafx.properties, lib/libt2k.dylib, lib/libAppleScriptEngine.dylib, COPYRIGHT, lib/fonts/LucidaTypewriterBold.ttf, lib/meta-index, bin/servertool, lib/libdecora_sse.dylib, lib/libfxplugins.dylib, lib/libmanagement.dylib, lib/images/cursors/invalid32x32.gif, lib/ext/zipfs.jar, lib/libprism_sw.dylib, lib/management/jmxremote.password.template, lib/libjava.dylib, lib/classlist, lib/psfontj2d.properties, lib/cmm/LINEAR_RGB.pf, lib/jsse.jar, lib/fonts/LucidaSansDemiBold.ttf, lib/libjfxwebkit.dylib, lib/ext/sunjce_provider.jar, lib/libjsig.dylib, lib/fonts/LucidaBrightDemiItalic.ttf, lib/libmlib_image.dylib, lib/security/java.security, lib/libdcpr.dylib, lib/cmm/CIEXYZ.pf, bin/java, lib/libnet.dylib, lib/liblcms.dylib, lib/libosx.dylib, Welcome.html, bin/pack200, bin/policytool, lib/libjdwp.dylib, lib/libosxapp.dylib, lib/server/libjvm.dylib, bin/rmiregistry, lib/security/cacerts, lib/jli/libjli.dylib, lib/management/snmp.acl.template, bin/keytool, lib/fonts/LucidaSansRegular.ttf, lib/security/blacklisted.certs, lib/libfontmanager.dylib, lib/libnpt.dylib, lib/logging.properties, lib/libsunec.dylib, lib/images/cursors/motif_LinkNoDrop32x32.gif, lib/libverify.dylib, lib/ext/sunpkcs11.jar, lib/ext/jfxrt.jar, lib/libj2pcsc.dylib, lib/calendars.properties, lib/jfxswt.jar, lib/libjavafx_iio.dylib, lib/libjaas_unix.dylib, bin/unpack200, lib/security/trusted.libraries, lib/cmm/sRGB.pf, lib/fontconfig.bfc, lib/server/libjsig.dylib, bin/jjs, lib/libj2gss.dylib, lib/management-agent.jar, lib/libdeploy.dylib, lib/rt.jar, lib/cmm/GRAY.pf, lib/libjfxmedia.dylib, lib/images/cursors/cursors.properties, lib/libawt_lwawt.dylib, lib/libbci.dylib, lib/hijrah-config-umalqura.properties, lib/libjavafx_font.dylib, lib/jce.jar, lib/libdt_socket.dylib, lib/jspawnhelper, lib/management/jmxremote.access, lib/jfr/default.jfc, lib/deploy.jar, lib/libglass.dylib, lib/libjawt.dylib, lib/net.properties, lib/resources.jar, THIRDPARTYLICENSEREADME-JAVAFX.txt, lib/libgstreamer-lite.dylib, lib/libosxui.dylib, lib/ext/meta-index, lib/libinstrument.dylib, lib/ext/nashorn.jar, lib/tzdb.dat, lib/images/cursors/motif_MoveNoDrop32x32.gif, lib/libzip.dylib, lib/libresource.dylib, lib/jvm.cfg, lib/libj2pkcs11.dylib, lib/libjfxmedia_qtkit.dylib, lib/flavormap.properties, lib/charsets.jar, LICENSE, lib/libosxkrb5.dylib, lib/images/cursors/motif_CopyDrop32x32.gif]}, appResources=RelativeFileSet{basedir:/var/folders/_w/k9hb3psj3112n5pyn8q2qbj00000gp/T/testBundlerWorkDir4321292194462776855/jars, files:[testFxAppWithUtil.jar, Util.jar]}, mainJar=RelativeFileSet{basedir:/var/folders/_w/k9hb3psj3112n5pyn8q2qbj00000gp/T/testBundlerWorkDir4321292194462776855/jars, files:[testFxAppWithUtil.jar]}, classpath=testFxAppWithUtil.jar:Util.jar}

This is only applicable to Java API, so the corresponding javapackager and Ant stuff works.