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[netCDFJava #LYK-546339]: Problem with netCDF-Java when also using libjhdf5

Unfortunately, we (Unidata) have not seen this issue either.
At the Java level, having two different JNI APIs to the same
library should probably be ok. However I might speculate
about some possible issues:
1. order of loading - do you know if the netcdf-c library is being
   loaded before or after  jarhdf5-3.3.2.jar?
2. do you know if the HDF5 versions being used are the same?

> 
> My project, the TESS Science Processing Operations Center (SPOC) at NASA 
> Ames, is using the netCDF Java API to run our datastore: we use 
> netcdf4-4-6.10.jar and netcdfAll-4-6.8.jar . As I understand it, the Java API 
> then uses libnetcdf.so, which in turn makes use of libhdf5.so, both through 
> JNA. We are using libhdf5.so.10.3.0 and libnetcdf.so.13.0 .
> 
> So far so good, this has worked well for us for a couple of years. However:
> 
> Recently we decided that we wanted to also use straight HDF5 in our Java code 
> for another purpose (very long story). For this we are using the HDF5-Java 
> implementation available from the HDF5 group: jarhdf5-3.3.2.jar, which in 
> turn uses libjhdf5.so.3.3.2 . This library is accessed via JNI.
> 
> Unfortunately, we observe problems when we use both of these libraries in a 
> single executable on linux:
> 
> What we observe is that there appear to be confusion problems when both 
> libraries are loaded. So for example, the netCDF library loads and writes an 
> array to disk; after that, we are unable to read HDF5 arrays and get errors 
> when attempting to read attributes. As far as we can tell the HDF5 array in 
> question is valid.
> 
> I realize that this may be kind of vague. I’m writing in hopes that somebody 
> at netCDF has heard about this kind of problem before and knows what to do! 
> AFAICT the folks at HDF5 are not familiar with this issue.
> 
> Thanks,
> -PT
> 

=Dennis Heimbigner
  Unidata


Ticket Details
===================
Ticket ID: LYK-546339
Department: Support netCDF Java
Priority: Normal
Status: Open
===================
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