Originally posted by Jonas X. Yuan:
Maybe, Liferay could provide better solution for you to migrate from existing frameworks to portals and portlets.
I heard that the way Liferay supports migration of portlets is that we can migrate JSR-168-compliant portlets to Liferay, but we can migrate Liferay portlets to other JSR-168-compliant portals. I don't have any experience in migrating portlets across different platforms like this. But this is what I heard from the Liferay communities.

Co-author of SCMAD Exam Guide, Author of JMADPlus
SCJP1.2, CCNA, SCWCD1.4, SCBCD1.3, SCMAD1.0, SCJA1.0, SCJP6.0