Configuration

ENV	java system property	default value	comment
JARS_VERBOSE	jars.verbose	false	some more output
JARS_DEBUG	jars.debug	false	loads of extra output
JARS_QUIET	jars.quiet	false	no more warning on conflicts
JARS_VENDOR	jars.vendor	true if jar-dependencies is development false if jar-dependencies is runtime	vendors transitive jar-dependencies inside the gem while installing the gem.
JARS_LOCK	jars.lock	Jars.lock	lockfile to use. on the first require all jars from this lockfile get required/loaded. it assumes that all the jars a resolved and can be found on the $LOAD_PATH or on Jars.home
JARS_RESOLVE	jars.resolve	false	resolve the jar dependencies as given in Jars.lock.
JARS_HOME	jars.home	{local maven repository as configured with maven}	this is the place where the jars get cached.
JARS_MAVEN_SETTINGS	jars.maven.settings	$HOME/.m2/settings.xml	along the local maven repository you can configure mirrors, proxy and access credentials for the same and more.
JARS_LOCAL_MAVEN_REPO	jars.local.maven.repo	{local maven repository as configured with maven}	can be any directory and is a cache for downloaded jars file via maven. default is to share this cache with maven itself. basically used for testing to separate the cache from Jars.home where jars are lookup for loading/requiring them.
JARS_SKIP	jars.skip	false	skip the post_install hook of rubygems, i.e. skip any action on jar-dependencies during the installation of gems.

proxy settings

beside the maven settings jar-dependencies obeys the proxy settings from rubygems config which takes priority to the one from the maven settings.