"J2EE and .Net are two evil princes that are fighting
for the crown of the dead king COBOL".
Picking between these two is like picking a religion
and I have picked Java, and everyday I pray for it!
But I also have in mind that Microsoft with their
horrible (both technically and philosophically)
products is the richest company in the world and Sun
has been doing worse and worse year after year
(although Microsoft's money comes from Windows and its
not going to keep flowing as strongly forever).
Microsoft is also the smartest software  company when
it comes to the business aspects (make a cute little
product that is very very simple to use in the
surface, but it doesn't matter what crap lies
underneath). On the other hand, the power of Java
comes from the community and is the power of freedom.
This is almost becoming like the classic legends of
the war between the Free and the Rich and we all know
that the rich will win the battles but the Free will
win the war since the Rich’s source  of power will
diminish as he spends his money on the battles but the
source of power of the Free won’t go anywhere.
What will happen in the short term is that if the Rich
that likes freedom (IBM, Oracle) support  Spring, .Net
will be beat sooner rather than later but if they
don’t, you might need to learn .Net to pay the bills,
but I am sure that Java or something like Java will
come out glorious in the end.