It is interesting and I grasp the concepts but actually doing those
things myself is beyond me.
Learn to use the command line and teach yourself the basics of writing
shell scripts. Without these basic skills you're essentially crippling
yourself.
If you understand any non-UNIX OS, get a copy of "Linux in a Nutshell".
If don't know any OS at a reasonable depth, i.e you're not a power user,
you need a less terse book. I hear that 'Linux for Dummies' is OK but
haven't used it myself because I started using UNIX and UNIX clones in
the late '80s, so the way Linux works was just more of the same when I
started to use it.
I can't find any documentation for command line java and javac.
"java -?" or "man java" on the command line. Same for javac.
Or download and read the JDK documentation - this is a separate download
from the JDK or JRE packages. If you don't have it installed you should
do so.