[Exist-open] xquery error messages

[<mcu...@co...>]

Where are the error messages from the xquery processor stored? 

For example, when using the GUI interface... 

if I run this query: 

let $hello := "hello" 
return $goodbye 

I get this error message: 


org.xmldb.api.base.XMLDBException: XPDY0002 : variable '$goodbye' is not set. [at line 2, column 9] [at line 2, column 9] 
at org.exist.xmldb.RemoteXPathQueryService.compile(RemoteXPathQueryService.java:127) 
at org.exist.client.QueryDialog$QueryThread.run(QueryDialog.java:469) 
Caused by: org.exist.xquery.XPathException: XPDY0002 : variable '$goodbye' is not set. [at line 2, column 9] [at line 2, column 9] 
at org.exist.xmldb.RemoteXPathQueryService.throwXPathException(RemoteXPathQueryService.java:191) 
at org.exist.xmldb.RemoteXPathQueryService.compileAndCheck(RemoteXPathQueryService.java:154) 
at org.exist.xmldb.RemoteXPathQueryService.compile(RemoteXPathQueryService.java:125) 
... 1 more 
Caused by: org.exist.xquery.XPathException: XPDY0002 : variable '$goodbye' is not set. [at line 2, column 9] [at line 2, column 9] 
at org.exist.xmldb.RemoteXPathQueryService.throwXPathException(RemoteXPathQueryService.java:191) 
at org.exist.xmldb.RemoteXPathQueryService.compileAndCheck(RemoteXPathQueryService.java:154) 
at org.exist.xmldb.RemoteXPathQueryService.compile(RemoteXPathQueryService.java:125) 
at org.exist.client.QueryDialog$QueryThread.run(QueryDialog.java:469) 


But where is this message stored? 

Thanks, 
Morgan