J2SE 5.0 has XPath XPI which is different from DOM Level 3. Any ideas why?

Hi All,

I am trying to use some standard XPath APIs to parse XPath expressions.

J2SE 5.0 (JAXP) has XPath 
<http://java.sun.com/j2se/1.5.0/docs/api/javax/xml/xpath/package-summary.html> 
API, which looks in someways similar to DOM Level 3 XPath 
<http://www.w3.org/TR/DOM-Level-3-XPath/> API. But both have different 
interface names and definitions. Can someone tell me why is that 
difference and if I want to use DOM Level 3 XPath APIs, is there any 
standard ways of doing it in Java?

Thanks in advance.

Kind Regards,
Prakash