If you close an IndexWriter more than once, the release of the writeLock 
  creates a NullPointerException.
You should clean your code and close your writer only once. Anyway, I 
don't know why there's no test on the 'writeLock' as in the 'finalize' 
method.
I think it's a little error, so I suggest the attached patch to fix that.

Franck Brisbart


jitender ahuja wrote:
> Hi,
>      Can anyone tell what is the cause of error for the following error 
> as the source of error is not any of the following:
> a) Index directory closing after each file of the directory (to be 
> indexed) : verified by the changing directory size, with the changing
>  number of files to be indexed
> b) IndexWriter object being closed out : verified by checking the 
> IndexWriter object ( here, writ) being a non-null object, by the line:
>         System.out.println(writ != null); in the attached code
>  
>  
> Error output:
>  java.lang.NullPointerException
>         at org.apache.lucene.index.IndexWriter.close(Unknown Source)
>         at IndexDatanew.indexDocs(IndexDatanew.java:89)
>         at IndexDatanew.indexDocs(IndexDatanew.java:50)
>         at IndexDatanew.main(IndexDatanew.java:25)
>  
> The code that causes this error is working fine otherwise (i.e. for 
> indexing purposes) and is "attached"; the output in detail for a
> directory of 2 files is also attached.:
>  
> Thanks
> Jitender
> 
> 
> ------------------------------------------------------------------------
> 
> C:\lucroche>java IndexDatanew E:\freebooks\books\whole\jiten
> Index Directory: E:\freebooks\books\whole\jiten
> 2
> E:\freebooks\books\whole\jiten\Copy of TIJ3_c.htm
> adding: E:\freebooks\books\whole\jiten\Copy of TIJ3_c.htm
> File contents from buffer:
> E:\freebooks\books\whole\jiten\Copy of TIJ3_c.htm
> false
> E:\freebooks\books\whole\jiten\TIJ3_c.htm
> adding: E:\freebooks\books\whole\jiten\TIJ3_c.htm
> File contents from buffer:
> E:\freebooks\books\whole\jiten\TIJ3_c.htm
> false
> java.lang.NullPointerException
>         at org.apache.lucene.index.IndexWriter.close(Unknown Source)
>         at IndexDatanew.indexDocs(IndexDatanew.java:89)
>         at IndexDatanew.indexDocs(IndexDatanew.java:50)
>         at IndexDatanew.main(IndexDatanew.java:25)
>      
> 
> 
> ------------------------------------------------------------------------
> 
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-- 
Franck Brisbart
R&D
http://www.kelkoo.com