2nd time in righting as damn my lappy wouldnt response. Wrote a long message now pissed off! So keeping it brief here and summary of what I think I wrote before, ha!
I have not done any java until a few years back when I got put into a project at work. For me personally I found it very easy to pick up but I did have a technical background so it helps . The IDE's used really help the developer in that the intellisense style menu shows all methods and properties of objects. The most common free IDE I have come across is Eclipse. IBM's Rational tools like RAD and RSA are based on Eclipse also.
If you are gonna go into Java and then move onto more of the web stuff (which is where a lot of work seems to be right now) then look at more open source stuff. In particular look at Hibernate and Spring. Pretty easy to use and get to grips with.
As part of knowing Java, something you must know is the world of object orientation. Stuff like what is encapsulation, inheritance etc. This is more theory but will help you a lot in Java. Another thing to note though not so important in the early stages of learning is the various design patterns.
I have attached something which you may find useful. I have had it ages in my collection of ebooks, I just never got round to looking at it but hopefully you may find it useful. Password of archive is the name of this site minus the prefix and suffix.
For the web side of developing have a look at Tomcat since its free and Eclipse works well with it.
For me personally I didnt think all that of Java though the work I did (involving Faces and Spring MVC) can be challenging.
Okay, I did write more but think I covered most in the shortened form above.
Hope what I wrote helps and good luck if you do decide to go down that route.