Natural Languga Processing and keyword finding for Java : assume we have a forum where a user can create topics and discuss about things. It is in my interest that the forum is serious and does not contain exchange of illegal things or organization of illegal meetings e.g. drug trade or child pornography. My application is written in Java, is there a Framework or an WebApi that can find and identify words or semantic meanings of the things user wrote to check  there are no illegal things going on? 