title: Which is the best way to store different versions of the file which is of the form HashMap and the User can ask for any Version?
body: <p>I have a file of the form HashMap&lt;Property, Value&gt;. For this file, there is an update in one/all of the field for each version. I wanted to know what is the best way to store this type of file s as to have best runtime with efficient space utilisation ?</p>