l2fprod-common-tasks.jar is part of media-tv/tvbrowser-2.2.1 Its the last .jar file which is currently not in portage. See bug #135554 for on-going work for a new tvbrowser ebuild.
For now in Java overlay - https://overlays.gentoo.org/svn/proj/java/migrated-java-experimental-overlay/dev-java/l2fprod-common/ Also its jreleaseinfo dependency. Had to package distfile from cvs checkout, because the source they bundle comes with no build system. The package builds everything from l2fprod-common that needs no extra deps (i.e. no spring and jcalendar/nachocalendar stuff, can be added later as useflags or separate packages, if need be). If you need just the tasks.jar, use "java-pkg_jar-from l2fprod-common l2fprod-commons-tasks.jar" in your ebuild. Please test and report if it works for you and then I will add it to main tree and put distfile on mirror.
Using this ebuild from your overlay builds tvbrowser-2.2.1 just fine. When is this ebuild going to be imported to the gentoo.org portage-tree?
jreleaseinfo added to portage, l2fprod-common distfile uploaded to mirror system.
Commited to portage tree. amd64, please keyword ~arch: dev-java/jreleaseinfo-1.3.0 dev-java/l2fprod-common-6.9.1
Fixed in CVS, thanks