how to parse xml to hashmap?

I have an example of an xml I want to parse

 <?xml version="1.0" encoding="utf-8"?>

<Details>
    <detail-a>

        <detail> attribute 1 of detail a </detail>
        <detail> attribute 2 of detail a </detail>
        <detail> attribute 3 of detail a </detail>

    </detail-a>

    <detail-b>
        <detail> attribute 1 of detail b </detail>
        <detail> attribute 2 of detail b </detail>

    </detail-b>


</Details>

I would like from this xml to write a method that will parse it to hashmap that the key is a string and the value is a list of strings.

for instance : key "detail a" value={"attribute 1 of detail a","attribute 2 of detail a","attribute 3 of detail a"}

and so on..

what is the best way to do this ? because I got confused :\

thanks