Java N-Dimensional Sparse Matrix

问题:

I have a 4-dimensional huge sparse matrix and I need to know the best data structure to manage my information using Java.

I read from this topic Sparse matrices / arrays in Java and it says that Tries is better than Hash Tables when matrix is so formatted. Unluckly the most authoritative answer talks about 2D-dimension matrices and I haven't found anything about N-dimensional ones.

Thank you in advance for your reply