where is the Tree in java.util.Collections?

I allways wandered why there's no generic api defined for trees under the umbrella of java.util.Collections api. And every time I needet to handle tree-structured data I ended up writing quite the same code with slight modifications once again. So I recently started to create an API that is both generic and powerfull enough to never again write a line of code just to handle objects that are organized in graphs.

Please read through the javadoc and tell me your thoughts!