Change value in XML file via Android Java

I want to change the "value" and "defaultValue" of the "drop" that contains "a33"

<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>
<settings version="-1">
  <setting id="1" name="a1" value="VAL555" drop="a12" defaultValue="VAL555" default="false" tag="null" />
  <setting id="2" name="a2" value="VAL555" drop="a22" defaultValue="VAL555" default="false" tag="null" />
  <setting id="3" name="a3" value="VAL555 <== I WANT TO CHANGE THIS" drop="a33" defaultValue="VAL555 <== I WANT TO CHANGE THIS" default="false" tag="null" />
  <setting id="4" name="a4" value="VAL555" drop="a44" defaultValue="VAL555" default="false" tag="null" />
  <setting id="5" name="a5" value="VAL555" drop="a55" defaultValue="VAL555" default="false" tag="null" />
</settings>

I want to do this for an app in Android Java

Currently, I can't go anywhere. I have no idea where to start from, or where to look for.