> I put log4j-core.jar in my classpath and the property but i get:
> og4j:ERROR No appenders could be found for category
> (org.firebirdsql.ngds.GDS_Impl).
> log4j:ERROR Please initialize the log4j system properly.

You have to put a file log4j.properties into your classpath, it should
have following content:

log4j.rootCategory=DEBUG, Default
log4j.appender.Default=org.apache.log4j.FileAppender
log4j.appender.Default.File=jaybird.log
log4j.appender.Default.layout=org.apache.log4j.PatternLayout
log4j.appender.Default.layout.ConversionPattern=[%c{1},%p] %m%n
log4j.appender.Default.Append=true

Roman