NPE in ExportFactory prevents JabRef from starting

[Siedlerchr]

Start JabRef -> NPE
@tobiasdiez You have introduced a circular dependency
In the creation of the exportFactory the getfileExtension is called, which internally acesses Globals.exportFactory which is at that point not yet initialized

11:06:58.982 [AWT-EventQueue-0] ERROR org.jabref.FallbackExceptionHandler - Uncaught exception occurred in Thread[AWT-EventQueue-0,6,main]
java.lang.NullPointerException: null
	at org.jabref.preferences.CustomExportList.getFileExtension(CustomExportList.java:47) ~[main/:?]
	at org.jabref.preferences.CustomExportList.createFormat(CustomExportList.java:101) ~[main/:?]
	at org.jabref.preferences.CustomExportList.readPrefs(CustomExportList.java:78) ~[main/:?]
	at org.jabref.preferences.CustomExportList.getCustomExportFormats(CustomExportList.java:64) ~[main/:?]
	at org.jabref.logic.exporter.ExporterFactory.create(ExporterFactory.java:67) ~[main/:?]
	at org.jabref.JabRefMain.start(JabRefMain.java:146) ~[main/:?]
	at org.jabref.JabRefMain.lambda$0(JabRefMain.java:53) ~[main/:?]