New to Java

Hi All!
I am new to Java and have a question!

In my control panel, I have Java 2 Runtime Environment, SE V.1.4.2_03 and it is 136.00 MB. That appears to be the first program download???
Then I have J2SE Runtime Environment 5.0 Update 3, Version 1.5.0.30 which is 117.00 MB.
Then there is J2SE Runtime Envirtonment Update 6, V. 1.5.0.60 which is 119.00 MB.
Then I also have Updates 9, 10 and 11 Version 1.5.0.110, which are 119 MB, 120MB and 120 MB respectively.

Do I need ALL OF THESE programs in my computer, or can I delete the first ones, and just keep the most recent???
(I always thought updates had much smaller MBs. The large number of MBs leads me to think that a whole new program has downloaded and possibly the original programs are outdated or overwritten???)

In fact, I don't even remember downloading these updates. Does anyone know under what other names I might be downloading these program updates?
(We do play quite a few games in this house!)
THANKS!!!
MariG