Weak Java performance with Sony Ericsson T610?

I was very surprised by the weak Java benchmark results of Sony Ericsson
T610 and T616 phones published at http://www.jbenchmark.com/. While Sony
Ericsson P800 achieved the second best result, T610 and T616 achieved the
worst results at all. P800 is a Symbian-based smartphone and it is able to
run native EPOC32 applications, so the Java applications will probably run
on T610 and T616 much more often. T610 and T616 were outpaced even by Nokia
3410.

I would like to know what causes the weak Java performance. CPU and memory
do not seem to be an issue at T610, so I suspect a troubled Java Virtual
Machine implementation. Will there be any JVM update available? Which Java
benchmark do you consider the most relevant?