Hey all,
This is my first post. For the unpatient or time starved, my subject line sums it up. I'm trying to get your thoughts on the best way to learn several large, and I mean very large
java projects for a very well known public company you all have heard of. Technologies are Java,
JBoss, Oracle, Hibernate,
Maven,
EJB, Mercurial, Linux and using Eclipse as the
IDE. How can I come up to speed on the custom code as quickly as possible? The problem is that of course I can't be a drain on the team who are all very busy. I can get an hour here or there from them, but I don't want to be a nuisance. Oh and by the way

... did I mention I have coded very, very little in Java (total beginner) and have zero experience save Linux (I'm advanced there)?
For those with more time or curiosity... (and once you recover from your good laugh, and tell me of the impossibility of it, read on)
A quick background. I have been a professional developer, lead, architect, and IS manager alternatively for at least 15 years. I worked mostly on legacy systems written in IMSBasic (huh? didn't think you had heard of it... it's a long dead language) on huge servers that processed orders for Fortune 500 companies (It backended www.lenovo.com and www.shoptoshiba.com and many others). I then specialized in the middleware servers running Apache, ModPerl, Perl, and XSL translation. I have written hundreds of thousands of lines of code probably, some extremely complex and algorithmic to get around limitations in the language to extend the life of the servers in an increasingly technical world.
NOW
I got laid off because the stuff was all replaced with SAP and I had no interest in ABAP coding, and was a manager at that time anyway, making great money, but my team was let go when we shuttered the legacy system, and so was I. But...
One of my managers who I used to report to when I was a developer remembered how good I was (I was top notch, and I'm a member of Mensa... I don't say that to brag, but to hopefully to give some context to assist with any answers you might have. I can learn fast). He saw I was in a bind and had been searching for a senior java developer for quite some time, with no success. Long story short, he's giving me a once in a lifetime shot to come up to speed on this, knowing it will take me a while, but with the hope that he gets a known commodity and a solid long term investment. My tentative plan is 6 months to be productive at least with smaller modifications and fixes.
I have been given an opportunity many would envy, and I don't take it lightly. I did earn it by proving myself to this guy who moved on to this company, and now that is paying off. But I can't fail at this. I will be spending 10 hours a day minimum on this endeavor (I am married with kids so I can't go in a hole for six months). So far I have all the technologies installed, I have access to
test and prod servers, I have used Mercurial to get the code base, and used Maven to build it in Eclipse. I have my first assignment, a debug of a long time annoyance issue for users... just to get into the code. I've used a month to get to this point due to new hire stuff, access, yada yada... all the corporate junk.
Now it's go time. I have a few books, but I need to understand this code while understanding java at the same time. So... thanks for any help?
--Chris