eclipse and XML problem

First let me ask you about the XML.
I am using javax.xml.parse rs.DocumentBuil der from the JDK to parse a
XML file to Documnet. My question is: Is there in the JDK a package or
classes to convert from Document to XML like it's in the xcerces
(org.apache.xml .serialize.*). I am lookin something like this in the
JDK. I should use only the standard JDK (no external packages).
If anybody could help i will be thankfull.

And the other thing: Is there a way in eclipse to set more then one
Documentation api. There is only one place for it and no ";" ","
helps.
I want to put in eclipse j2se, j2ee and external javadocs, to access
it with SHIFT+F2... but how?

jivko