Apache SOAP 2.3.1 and Java

Does anyone have any experience running Apache SOAP 2.3.1 and Java 1.5/1.6?

Currently I'm using Java 1.4 but I would like to update to 1.5/1.6, but 
I've noticed that under Java 1.5 on some Clients my SOAP calls sometimes 
slow down to a factor of 100-1000 times slower - does anyone have any 
experience with this problem?  Any tips?  I am unable to reliably 
reproduce this problem - it could be client configuration setting that 
I've missed, but it always only surfacing under Java 1.5+ (even on dual 
Java installations)

Basically I want a smooth transition path for my Java Web Start 
application - involving either first changing for a new Java 
Installation and then later using its newer built in SOAP/Web Service 
support or changing my SOAP implementation to a new external library, so 
which supports Java 1.4 and 1.5/1.6.

Does anyone have any ideas?

Thanks

Martin Cavanagh
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