How do I protect and market my code?

Basically I had a over the summer assignment which I used to develop a piece of software which I guess will sell around 50 - 70 bucks a copy.

To make this clear. The final code is in Java (a requirement).

Now I was think about marketing my little creation however I'm faced with two problem:

1, I need to provide full documentation to the Lecturers. How do I go about preventing them from stealing my code/methodologies used? Would simple copyright be enough?

2. How do I bundle the software? How do I sell it? Should I partner with a publisher or should I just sell the code to a software company? I will need bi-yearly maintenance at least.
How do I protect said software from getting cracked?

How /prog/ has some experience on this already!
Thanks for helping out!

PROTECT AND MARKET MY ANUS

Now seriously, Java bytecode can be reverse-engineered quite easily. It's not the best language for trade-secret enterprise solutions. Also note that the more effort you put to copy-protect your work, more hackers will be attracted and it will be breaked earlier. So use a simple protection that won't consume you many hours and assume that some copies will be run without having paid you.

Summarizing, estimate the quota of pirated copies and rise the license fee accordingly.