Nltk stanford pos tagger error : Java command failed

Question

I'm trying to use `nltk.tag.stanford module` for tagging a sentence (first like wiki's example) but i keep getting the following error : ``` Traceback (most recent call last): File "test.py", line 28, in <module> print st.tag(word_tokenize('What is the airspeed of an unladen swallow ?')) File "/usr/local/lib/python2.7/dist-packages/nltk/tag/stanford.py", line 59, in tag return self.tag_sents([tokens])[0] File "/usr/local/lib/python2.7/dist-packages/nltk/tag/stanford.py", line 81, in tag_sents stdout=PIPE, stderr=PIPE) File "/usr/local/lib/python2.7/dist-packages/nltk/internals.py", line 160, in java raise OSError('Java command failed!') OSError: Java command failed! ``` or following `LookupError` error : ``` LookupError: =========================================================================== NLTK was unable to find the java file! Use software specific configuration paramaters or set the JAVAHOME environment variable. ================================================================…

Accepted Answer

If you read through the embedded documentation in the nltk/internals.py (lines 58 - 175) you should find your answer easy enough. The NLTK requires the full path to the Java binary.

If not specified, then nltk will search the system for a Java binary; and if one is not found, it will raise a LookupError exception.

You have a couple of options I believe based on a bit of research:

1) Add the following code to your project (not a great solution)

```
import os
java_path = "path/to/java" # replace this
os.environ['JAVAHOME'] = java_path
```

2) Uninstall & Reinstall NLTK (preferably in a virtualenv) (better but still not great)

```
pip uninstall nltk
sudo -E pip install nltk
```

3) Set the java environment variable (This is the most pragmatic solution IMO)

Edit the system Path file /etc/profile

```
sudo gedit /etc/profile
```

Add following lines in end

```
JAVA_HOME=/usr/lib/jvm/jdk1.7.0
PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
export JAVA_HOME
export JRE_HOME
export PATH
```

Nltk stanford pos tagger error : Java command failed

Solution

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