You could work on a cool eclipse or netbeans plugin. Something for Android may be interesting as well.
Welcome to the league. I would suggest the two best examples of successful opensource philosphy: Eclipse Any Apache project.
No offense, but I don't know of any large open-source projects that are looking for novice contributors. Open Office and Firefox are big projects; if I were the organizer I would not be soliciting new programmers to contribute. There are lots of smaller ones, though.
I don't know the Java world, but I'd suggest looking into a tool or utility with a plug-in model, where you can contribute something stand-alone, so that your work does not present a disruption or risk to anything else that's going on. One example, not in Java, that I know of that fits this pattern is a C#-based screen-snap tool called Cropper. It's a screen shot utility hosted on Codeplex.It's based on a plug-in model, so that each "destination" for a screen shot can be a different plug-in.
The various plugins are managed as a separate project on Codeplex. For example, there are plugins that: save to jpg save to PNG save to Imgur.Com save to Flickr send to Paint.NET. Exe etc Writing a plugin for something like that is a reasonably-sized effort for someone starting out.
This is just an example. I know you said you're working in Java. I suggest that you find a similarly structured project based on Java where you can take a separable unit of work on, for you and maybe one or two teammates, if you have a team.
Have to agree with Cheeso. Perhaps one of those projects would be looking for some documentation help, but probably not any coding help from a novice. Do you know Python?... I use Jython (an open source java project) and know that the documentation is lacking ;-) Android is cool too and pretty young.
I know the Ringdroid application is in need of fade-in, fade-out, and amplify features.
If I were a novice and wanting to contribute to an open source project (or being forced to :-) ), I'd think about not tackling anything big first....there are lots of worthwhile things that can be done by beginners. For example, I personally like Joomla. It's a pretty good Content Management System (CMS).
One of the best things I think about Joomla is that it has various templates that you can use in the creation of your website. You could create a template. A tutorial for this is at: docs.joomla.org/Tutorial:Creating_a_basi... look at how to contribute you can go to: joomla.org/about-joomla/contribute-to-jo... Good luck!
The single most important factor that will determine the project you contribute to is your interest in that project. If you already use a Open-Source Java code library/product, you already have a built a platform, and the next step would be to start contributing to it in forms of documentation/tips and code. Documentation is usually a easy and a good starting point for any project.
I shall narrate you a personal example- I started off contributing to the NetBeans Community Docs by contributing articles, and then went on to manage it for a year.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.