Having Trouble understanding CNI string allocation

Mon Sep 27 12:22:00 GMT 2004

 Thank you very much --
 How's about these random errors when doing all String
 allocation dynamically (i.e. java::lang::String * is
 only used for one call and then forgotten). Is this
 explainable from within CNI or should I try to find
 the misbehaviour in the JDBC driver ?
 BTW I'm sing gcj-3.3.3 as shipped with Fedora Core 2
 Thanks
 Sebastian
Andrew Haley wrote:
> Sebastian Kloska writes:
> > 
> > In an attempt to reduce the calls to JvNewStringUTF I was trying
> > to store the colum names I like it access in an array of
> > 'java::lang::String *', but after initializatons (as a none static
> > class array) and befor using these pointers in another class method
> > the strings seem to be gone. So it seems I do not realy understand
> > the concept of how long I'm alowed to hold a (valid ?) reference
> > to an JAVA object (e.g. String) and that somehow the garbage
> > collector is 'stealing' these from me....
>> The gcj garbage collector will recycle memory when it determines that
> there are no live references to it. The gc won't look inside
> structures allocated by malloc() or the C++ runtime library's new().
>> If you want to make an array of 'java::lang::String *' you had better
> make it a JArray<jstring>, not a C++ array, and you'd better make sure
> that a pointer to that jarray is live in a Java object somewhere, or
> the strings will be deallocated.
>> Andrew.

-- 
**********************************
Dr. Sebastian Kloska
Head of Bioinformatics
Scienion AG
Volmerstr. 7a
12489 Berlin
phone: +49-(30)-6392-1708
fax: +49-(30)-6392-1701
http://www.scienion.de
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