universalJavaApplicationStub

A shellscript JavaApplicationStub for Java Apps on Mac OS X that works with both Apple's and Oracle's plist format.

Why

Whilst developing some Java apps for Mac OS X I was facing the problem of supporting two different Java versions – the "older" Apple versions and the "newer" Oracle versions.

Is there some difference, you might ask? Yes, there is!

1. The spot in the file system where the JRE or JDK is stored is different:

• Apple Java 1.5/1.6: /System/Library/Java/JavaVirtualMachines/
• Oracle Java 1.7/1.8: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/

2. Mac Apps built with tools designed for Apple's Java (like Apple's JarBundler or the ANT task "Jarbundler") won't work on Macs with Oracle Java 7 and no Apple Java installed.

• This is because the Apple JavaApplicationStub only works for Apple's Java and their Info.plist style to store Java properties.
• To support Oracle Java 7 you would need to built a separate App package with Oracles ANT task "Appbundler".
• Thus you would need the user to know which Java distribution he has installed on his Mac. Not very user friendly...

3. Oracle uses a different syntax to store Java properties in the applications Info.plist file. A Java app packaged as a Mac app with Oracles Appbundler also needs a different JavaApplicationStub and therefore won't work on systems with Apple's Java...

So why, oh why, couldn't Oracle just use the old style of storing Java properties in Info.plist and offer a universal JavaApplicationStub?! 😡

Well, since I can't write such a script in C, C# or whatever fancy language, I wrote it as a shell script. And it works! ;-)

How it works

You don't need a native JavaApplicationStub file anymore...

The shell script reads JVM properties from Info.plist regardless of which format they have, Apple or Oracle, and feeds it to a commandline java call:

# execute Java and set
#	- classpath
#	- dock icon
#	- application name
#	- JVM options
#	- JVM default options
#	- main class
#	- JVM arguments
	exec "$JAVACMD" \
		-cp "${JVMClasspath}" \
		-Xdock:icon="$PROGDIR/../Resources/${CFBundleIconFile}" \
		-Xdock:name="${CFBundleName}" \
		${JVMOptions:+"$JVMOptions" }\
		${JVMDefaultOptions:+"$JVMDefaultOptions" }\
		"${JVMMainClass}"\
		${JVMArguments:+"$JVMArguments"}

It sets the classpath, the dock icon, the AboutMenuName (in Xdock style) and then every JVMOptions, JVMDefaultOptions or JVMArguments found in the Info.plist file.

The name of the main class is also retrieved from Info.plist. If no main class could be found, an applescript error dialog is shown and the script exits with exit code 1.

Also, there is some foo happening to determine which Java version is installed. Here's the list in which order system properties are checked:

1. system variable $JAVA_HOME
2. /usr/libexec/java_home symlinks
3. symlink for old Apple Java: /Library/Java/Home/bin/java
4. hardcoded fallback to Oracle's JRE Plugin: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java

If none of these could be found or executed, an applescript error dialog is shown saying that Java need to be installed.

What you need to do

Use whichever ANT task you like:

• the great opensource "Jarbundler"
• my JarBundler fork on github which supports MixedLocalization
• Oracle's opensource "Appbundler"

JarBundler example

Just place the universalJavaApplicationStub from this repo in your build resources folder and link it in your ANT task (attribute stubfile):

<jarbundler
	name="Your-App"
	shortname="Your Application"
	icon="${resources.dir}/icon.icns"
	stubfile="${resources.dir}/universalJavaApplicationStub"
	... >
	
</jarbundler>

The ANT task will care about the rest...

You should get a fully functional Mac Application Bundle working with both Java distributions from Apple and Oracle.

Appbundler example

Just place the universalJavaApplicationStub from this repo in your build resources folder and link it in your ANT task (attribute executableName):

<appbundler
	name="Your-App"
	displayname="Your Application"
	icon="${resources.dir}/icon.icns"
	executableName="${resources.dir}/universalJavaApplicationStub"
	... >
	
</appbundler>

The ANT task will care about the rest...

You should get a fully functional Mac Application Bundle working with both Java distributions from Apple and Oracle.

Missing Features

At the moment, there's no support for

• required JVM architecture (like x86_64, etc.)
• required JVM version (like 1.6+, etc.)
• etc...

An AppleScript dialog would be nice to prevent Java execution if the requirements aren't met.

License

universalJavaApplicationStub is released under the MIT License.