As Henry suggested if you learn the core concepts then learning the language is a matter of time. Software development fundamentals like concur OO concepts, multi-threading,performance, memory management, language fundamentals, best practices etc are same or similar in any language. No body knows what the fututure holds but currently Java especially JEE seems to be going strong.
Java enterprise technologies & frameworks like Spring, Hibernate(ORM),
JSF, Facelets, RichFaces (Ajax4JSF included) etc are quite popular. Recently I happen to work with RichFaces and quite impressed by it. EJB3 seems to be gathering momentum but only time will tell.
[ November 22, 2007: Message edited by: arulk pillai ]