Edit: This probably doesn't apply now based upon the example code you posted while I was responding. You mentioned using those two hashtables in other classes without qualifying them by name, which is not what your example indicates.
Of course it will cause ambiguity. The only way to use them without the class name would be to use static imports and if both variables have the same name they cannot be resolved.
Even if you could, why on earth would you?
Also note, unless you have specific reasons for needing Hashtable (if don't know what those reasons are then you don't need it), you should consider using HashMap instead.