Java: XMLUnit.setIgnoreWhitespace(true) causing weird output

I have an issue in the following code.

String xml1="<Akash><status>COMPLETE</status>"
                    +"<startedTime>23</startedTime></Akash>"; 
String xml2="<Akash><status>COMPLETE</status><startedTime></startedTime></Akash>";

Diff diff = new Diff(xml1,xml2);
diff.overrideElementQualifier(new ElementNameAndTextQualifier()); 
assertTrue("XML similar " + diff.toString(), diff.similar());

When I dont' write this following line in my above java code.

 XMLUnit.setIgnoreWhitespace(true) 

Assert gives an exception near "started time" that value of this node is not there, which is what I wanted, because value 23 is not present. But when I add this line (setIgnoreWhitespace) to the code before instantiating Diff class, Despite having same xml, this code passes the assert test.

I am really not getting what the **** is happening here. Please help me.

Note: I need XMLUnit.setIgnoreWhitespace(true) for equating two xmls which have space in between some of their nodes, otherwise code gives some other error.