json text file cause a NPE
upload a json file to an Derivate, go to Derivate browser -> will get a NPE in DerivateDirectoryTools.java:221 DerivateDirectoryTools.java:66 -> using URLConnection.guessContentTypeFromName don't get correct mime type
upload a json file to an Derivate, go to Derivate browser -> will get a NPE in DerivateDirectoryTools.java:221 DerivateDirectoryTools.java:66 -> using URLConnection.guessContentTypeFromName don't get correct mime type