I have read the documentation about XML and I want to know if I have
understood well. I can create an xml file  from the scratch creating
a DOM and inserting in it the tags  and the text  I want. Then, I can
write out this DOM with a transformer.
This is how I create an XML file, doesn't it?

And then, if I want to recover the XML file data somewhow, I can
create a DOM again to operate with it, or reading it by SAX.Is it
correct?

And, another XML question :). If I have something like this:

<hdp>
bla bla bla
<has_solution>
ble ble ble
</has_solution>
</hdp>

is this extract well formed? I mean, the text "bla bla bla" is in a
correct way?