com.oracle.tools.packager.Bundler.execute() returns null on MAC

STEPS TO REPRODUCE:

1. download jdk 10 build 36 from artifactory to install on mac machine.
2. set JAVA_HOME and PATH to refer to jdk 10 build 36 accordingly.
3. download the attachment "explodedmodulestest.zip" from bug.
4. extract the zip which results in explodedmodulestest folder and navigate to explodedmodulestest folder in command line.
5. execute the following commands at command line.

compile:
javac -d . JavaApiExplodedModulesTestInJDK10MAC.java

execution:
java testapps.JavaApiExplodedModulesTestInJDK10MAC

JDK 10 BUILD 36 ACTUAL OUTPUT:
==============================
stt-mac-42:Home gtee$ java -version
java version "10-ea" 2018-03-20
Java(TM) SE Runtime Environment 18.3 (build 10-ea+36)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10-ea+36, mixed mode)

stt-mac-42:explodedmodulestest gtee$ java testapps.JavaApiExplodedModulesTestInJDK10MAC
WebStart JNLP Bundler
Linux Application Image
DEB Installer
RPM Bundle
Mac Application Image
=========================Execution STARTS============================
parameters are {module-path=binjdk10, module=com.greetings/com.greetings.App1, name=WindowsApiSimpleExplodedModulesTestInJDK10MAC, appResources=RelativeFileSet{basedir:binjdk10, files:[custom.util, com.greetings]}, strip-native-commands=false}
Return value of execute is null
=========================Execution ENDS============================

6. Rename the folder explodedmodulestest\outdir\WindowsApiSimpleExplodedModulesTestInJDK10MAC to explodedmodulestest\outdir\WindowsApiSimpleExplodedModulesTestInJDK10MACBUILD36


7. Execute the steps from 1 to 6 for JDK 10 build 35

ACTUAL OUTPUT OF JDK 10 BUILD 35
===================================
stt-mac-42:Home gtee$ java -version
java version "10-ea"
Java(TM) SE Runtime Environment (build 10-ea+35)
Java HotSpot(TM) 64-Bit Server VM (build 10-ea+35, mixed mode)


stt-mac-42:explodedmodulestest gtee$ java testapps.JavaApiExplodedModulesTestInJDK10MAC
WebStart JNLP Bundler
Linux Application Image
DEB Installer
RPM Bundle
Mac Application Image
=========================Execution STARTS============================
parameters are {module-path=binjdk10, module=com.greetings/com.greetings.App1, name=WindowsApiSimpleExplodedModulesTestInJDK10MAC, appResources=RelativeFileSet{basedir:binjdk10, files:[custom.util, com.greetings]}, strip-native-commands=false}
Return value of execute is outdir/WindowsApiSimpleExplodedModulesTestInJDK10MAC.app
=========================Execution ENDS============================


ISSUE: Look for the String which follows after "Return value of execute is" in the above output.
JDK 10 BUILD 35 returns the folder path.
JDK 10 BUILD 36 returns null.