In order to run this project, you must go to https://meta.wikimedia.org/wiki/Data_dump_torrents and download the most recent enwiki-{date}-pages-articles.xml.bz2 file. It is a large file and will take time to download.
You must also modify this line https://github.com/cohen990/ConceptGraph/blob/master/src/main/java/ConceptGraph/App.java#L52 to point at the correct location on disk.