There have been a few threads about mutable numbers and I'll try to summarize the ideas.
1) What package/project should these classes go in?
My initial thought was lang.math, but if we create MutableByte, MutableString, or others non-numeric types, this isn't a good fit. lang.mutable may be a better fit.
2) What type of naming scheme should we use?
MutableInteger vs. MInteger vs. IntegerHolder vs. ?
3) Comparision between my (matth) initial implementation vs. Geronimos
I can't find the Mutable classes in Geronimo anymore. Perhaps they were removed?
One of the primary differences I noted was that the Geromino classes containeed additional methods such add add(int), subtract(int), and things like that. I find this similar to Henri's suggestion that MutableString contain StringUtils-like methods (split(), capitalize(), etc).
4) List of classes to have mutable versions of
- String
- Long
- Double
- Character