If you're looking for a jvm implementation, there are at least a couple:

https://github.com/rkapsi/patricia-trie https://github.com/jfager/functional-critbit

The latter is my own, with a focus on memory efficiency (by my benchmarks, it uses about 40% less space than patricia-trie for the same data set). Would love to get some extra eyes on it to figure out how to trim it further or speed it up.