Hibernate tools (the latest version) does not write to output script file (differences.sql) with hbm2ddl, uppdate="true" (target="compare").
Yet it writes to outputfile (schema.sql) in target="codegen".

<target name="codegen" description="create DDLs">
<hibernatetool destdir="${source.root}">
<configuration configurationfile="${conf.root}/hibernate.cfg.xml"/>
<hbm2ddl drop="false" export="false"
outputfilename="../schema.sql"/>
</hibernatetool>
</target>

<target name="compare" description="compare hbm with DB">
<hibernatetool destdir="${source.root}">
<configuration configurationfile="${conf.root}/hibernate.cfg.xml"/>
<hbm2ddl update="true" export="false"
outputfilename="../differences.sql" />
</hibernatetool>
</target>

Grateful to get tips or ideas. Thanks in advance!
/Kwan