I have to study a given quite large ontology represented with a triple store, to understand what kind of content is represented and how it's organized. I'm working with Protege 5.2.0 on a Windows 10 machine equipped with a Intel Core i7-6500U and 8 GB of RAM.
The main trouble reside on the heavyness of the triple store ( more or less 200 MB) that cause trouble on the ontology loading process in Protege and the management of ontology on the program itself.
I suceeded to solve the problem regarding the loading process increasing the avalaible memory for the JVM from 466 MB to 4 GB and single thread memory from 16 MB to 2 GB.
However, once the loading was successfully completed (as shown in the log file),even after a long time (more than 20 minutes) Protege results unusable because of the heavyness of the process. However, with a lot of effort, I succeeded to reach the Entity tab and I saw that, according to Protege, no entity,class or individual exists, but only annotations. In the log file, there's no error reported, but for each line a warning like
2017-05-12 14:54:54.937 [pool-2-thread-1] WARN OBOFormatParser LINE: 31 Expected white space at pos: 6 LINE:<http://minerva.atcult.it/rdf/000000362375> <http://purl.org/ontology/bibo/numPages> "14 p" .
Is the problem related to the triple store,or can it be solved using a particular plugin/setting on Protege?
As suggested in comment, I looked for errors in the ontology and I found one. In fact, the ontology couldn't be loaded because of a white space on a row of the nt file. Now it works, and Protegé loads the ontology correctly.