Tests fail due to different order of attributes (under Java 6)

When building wicket-1.3-SNAPSHOT using JDK 1.6.0_04 I get some test failures with messages all similar to this:

< <style type="text/css" id="org-apache-wicket-ajax-MockComponent1-0">
—
> <style id="org-apache-wicket-ajax-MockComponent1-0" type="text/css">

It seems like the element attributes have come in the "wrong" order (compared to the test case).

Since making the tests attribute order independent would probably be difficult, I suggest instead that the code is changed to guarantee that the attributes always come in the same order (TreeMap instead of HashMap?).