XPath.evaluate performance slows down (absurdly) over multiple calls

Try adding this code inside the loop at the top;

Node singleNode = nodes.item(i);
singleNode.getParentNode().removeChild(singleNode);

then run each evaluation using the singleNode variable instead of nodes.item(i);
(of course you change the name)

Doing this detaches the node you are working with from the large main document. This will speed up the evaluate methods processing time by a huge amount.

EX:

for(int i=0;i<nodes.getLength();i++)
{
    Node singleNode = nodes.item(i);
    singleNode.getParentNode().removeChild(singleNode);

    printTimestamp(1);
    xp.evaluate("atom:id/text()", singleNode );
    printTimestamp(2);
    xp.evaluate("samplens:fieldA/text()", singleNode );
    printTimestamp(3);
    xp.evaluate("atom:author/atom:uri/text()", singleNode );
    printTimestamp(4);
    xp.evaluate("samplens:fieldA/samplens:fieldB/&at;attrC", singleNode );
    printTimestamp(5);

    //etc.  My real example has 10 of these xp.evaluate lines

 }