From time to time I experiment with GATE NLP toolkit. Just now I tried to upgrade to the latest version (version 4) and run into really strange problem with ANNIE system not loading correctly. Later, when I uninstalled older GATE version, it stopped loading at all.
The problem is the user configuration file gate.xml that is stored in the shared location, usually home directory. On Windows, that is _C:\Documents and Settings[ProfileName]_.
One of those settings was pointing to where the plugins were loaded from and was still referring to GATE 3.1’s locations. That caused NullPointerExceptions in the GATE and everything was breaking from that point on.
I found this by using FileMon, but later realised that it might have been done easier by changing runtime.spawn property to false in GATE’s build.xml file that is used to start the program. Using ant to start a program is a new one for me, but I guess it makes sense in some cases. Setting the property to false shows the startup messages and the exception that the wrong directories cause.
I have deleted the old gate.xml and gate.session files in my home directory and everything started to work. Back to actually trying to use the software.