Re: 20050215:netCDF Java - NetcdfFile open method does not work as suggested

• To: Alain Boucher <boucher@xxxxxxxxxxxxxxxxxxxxxxx>
• Subject: Re: 20050215:netCDF Java - NetcdfFile open method does not work as suggested
• From: John Caron <caron@xxxxxxxxxxxxxxxx>
• Date: Wed, 16 Feb 2005 09:51:10 -0700

Unidata Support wrote:

------- Forwarded Message

To: support-netcdf-java@xxxxxxxxxxxxxxxx
From: "Alain Boucher" <boucher@xxxxxxxxxxxxxxxxxxxxxxx>
Subject: netCDF Java - NetcdfFile open method does not work as suggested
Organization: UCAR/Unidata
Keywords: 200502151901.j1FJ1u9O023527

Institution: Fisheries and Oceans Canada
Package Version: 2.2 (alpha)
Operating System: WindowsXP
Hardware Information: Intel P4
Inquiry: Hi there,

    I have downloaded the latest release of the Java NetCDF library.  I noticed 
that when using the open(String location) method on a NetcdfFile object, the 
method crashes when the file is empty (size of 0 bytes).

    I am not sure if the problem results from an ill-formed Netcdf structure or 
from the null size of the file, but the result is I get a OutOfMemoryError.

    However, the API suggests that it should throw an IOException() if the 
method fails.

    If I am misinterpreting what the method should do, does that mean I have to 
open a File object (from java.io) to first check if the file is a 0-length file?

    Thanks a lot in advance and congratulations on the great work you did of 
making that Java Netcdf library!  It is actually very helpful to our department!



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Hi Alan

When i run the NetcdfFile.main()

public static void main( String[] arg) throws Exception {

   try {
     String filename = "C:/data/bad/zero.nc";
     NetcdfFile ncfile = NetcdfFile.open(filename);

     System.out.println();
     System.out.println( ncfile.toString());

   } catch (Exception e) {
     e.printStackTrace();
   }
 }

I get:

java.io.IOException: Cant read C:/data/bad/zero.nc: not a valid NetCDF file.
   at ucar.nc2.NetcdfFile.open(NetcdfFile.java:231)
   at ucar.nc2.NetcdfFile.open(NetcdfFile.java:183)
   at ucar.nc2.NetcdfFile.open(NetcdfFile.java:141)
   at ucar.nc2.NetcdfFile.main(NetcdfFile.java:841)

can you try that and send me your output? thanks