Too many open files error

[GoogleCodeExporter]

When using semafor 2.1 on a file with a large number of sentences (more than 
50000), at some point it will crash because of a (catched) "Too many open 
files" error, that will then lead to a NullPointerException when the file 
descriptor will be used.

Traceback:
Processing batch of size:50 starting from: 49600
candidate_file_not_in_use (Too many open files)
Loading data....
Reading alphabet...
/path/to/semafor/semafor-semantic-parser/release/temp/64173.input.events.bin 
(Too many open files)
.0
Exception in thread "main" java.lang.NullPointerException
    at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
    at java.io.BufferedOutputStream.write(BufferedOutputStream.java:126)
    at java.io.FilterOutputStream.write(FilterOutputStream.java:97)
    at edu.cmu.cs.lti.ark.fn.utils.BitOps.writeInt(BitOps.java:74)
    at edu.cmu.cs.lti.ark.fn.parsing.CreateAlphabet.run(CreateAlphabet.java:102)
    at edu.cmu.cs.lti.ark.fn.parsing.ParserDriver.runParser(ParserDriver.java:345)
    at edu.cmu.cs.lti.ark.fn.parsing.ParserDriver.main(ParserDriver.java:117)

I checked in edu.cmu.cs.lti.ark.fn.parsing.CreateAlphabet.run, the stream is 
correctly closed, so I guess there is a missing call to close() somewhere else.

Original issue reported on code.google.com by theo.tro...@gmail.com on 5 Apr 2013 at 8:45