The Toolbox Project
This is a project for putting utility code - things for statistics, random numbers, graphs, trees, etc. I started this project mainly because I wanted to do some statistical and numerical work in Java, similar to what you can do in R, but did not know of any Java libraries that I could use. I also wanted to implement some graph algorithms and this was a good place to put that, but it may need to be moved to a different project in the future.
The latest development in the project is that it is being converted from an Ant/Netbeans based project to a Maven project so it can be listed in the Maven Central Respository. That way it can be used by other Maven projects by being listed as a dependency in the pom.xml instead of manually installing the jar, and it can be used by projects at algorithmia.com. Maven changes are currently in the maven branch and will be merged to master soon.
Codewise, one recent addition I have been working on is random number generation. The standard Java system has the ability to generate uniformly distributed random numbers between 0 and 1, but nothing more that I am aware of. This project contains implementations of binomial, normal, and exponential random numbers. They all use Java's Math.random(), but use it in a way that generates the correct distribution. For the normal and exponential distributions, it uses the inverse of the integral of the probability mass function as a shortcut (instead of say, simulating a series of binomials to generate an exponential, which is much slower).
I have been focusing on the stats stuff lately so the other stuff (graphs and trees) is still woefully incomplete.
I hope it can be useful for my projects, and maybe others' as well. It can also be a way of showing code I have written.