Bundles are actually built on top of ArrayMaps, which are memory-efficient implementations of Maps. For smaller ArrayMaps, a search takes less computational time than computing the hash for a similarly populated HashMap. But if you have more than severl hundred items in it, the HashMap will perform better.
Besides, Bundles were not designed to be general-purpose data structures.
原文：http://my.oschina.net/sfshine/blog/505853