apt-get questions

[Richard Kimber <rkimber@ntlworld.com>]

apt-get dist-upgrade is persistently holding back one package (j2sdk1.3). 
Why is this, and what, if anything, should I do?

Also, when I upgraded earlier, I found my kernel source had been upgraded.
I assume it just overwrote what was there previously, but it's not clear.
Is that what normally happens ?  And if so, how do I tell what release of
2.4.19 I had previously?

Thanks,

- Richard.