Scratch

Go into the system settings application, in the search bar type 'Software sources' click the first result, go into the window that pops up, click the 'other software' tab click the tick box next to canonical partners and then close that. Go into software centre, search for synaptic package manager, download it, run it, search for 'sun-java' get it, and other related stuff (it won't be called sun-java exactly) also I don't know whether you can get version 5, probably on 6 and 7.

No, probably to keep the live CD space down.

Another option would be to
sudo apt-get install default-jdk or find the package in synaptic(Package Manager)

Java 5 is outdated and if your book uses it don't worry; its all compatible.

what are you looking for?  Java, or iced tea, that allows you to view the java projects in the browser?  Because if you have java, it works.  You need IcedTea to view java in a browser. but you must have java to install icedtea.  Upgrade to 11.10, it is sooo much better.