Bug 95311 [javadoc wizard] Allow setting of -source 1.5 through UI
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javadocexport/JavadocOptionsManager.java
IVMInstallType[] jreTypes= JavaRuntime.getVMInstallTypes();
		for (int i= 0; i < jreTypes.length; i++) {
			IVMInstallType jreType= jreTypes[i];
			IVMInstall[] installs= jreType.getVMInstalls();
			for (int k= 0; k < installs.length; k++) {
				File res= getCommand(installs[k]);
				if (res != null) {
					return res;
				}
			}
		}
		return null;
	}
	private static File getCommand(IVMInstall install) {
		File installLocation= install.getInstallLocation();
		if (installLocation != null) {
			File javaDocCommand= new File(installLocation, "bin/javadoc"); 
			if (javaDocCommand.isFile()) {
				return javaDocCommand;
			}
			javaDocCommand= new File(installLocation, "bin/javadoc.exe"); 
			if (javaDocCommand.isFile()) {
				return javaDocCommand;
			}
		}
		return null;
	}
}