XSL processor in Java for xml and xsl strings

I am looking for a free or commercial xsl processor which
(1) is written in java (and preferably available in source code) for
integration into a servlet product
(2) can receive its xml and xsl inputs and provide html output through a
simple java function call, say as strings, rather than through the disk
(3) is likely to continue to be updated as the standard evolves and
stabilizes.

As a complete newcomer to the list, apologies if this ground has been
convered.

Thanks in anticipation of any help...

Zvi Schreiber


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