Combine the various jar sources into a single array of jars. @param libJars the jars specified in -lib command line options @param userJars the jars in ~/.ant/lib @param systemJars the jars in $ANT_HOME/lib @param toolsJar the tools.jar file @return a combined array @throws MalformedURLException i
(final URL[] libJars, final URL[] userJars,
final URL[] systemJars, final File toolsJar)