How use this Function? Or other meanning, why use it? (In java)

Question

Public static HashMap<string, string> makeMap(ArrayListe <string> object)

Answer 1

to store value-value(s) pair, eg dictionary
or for store hash of value, it means store long value with short value suitable for fast search, or security
it permits null, is unsynchronized (not suitable for multithread) and is unsorted