File Annoation Tab gives NPE when PDF is not avaiable

[Siedlerchr]

Entry with linked PDF:
file = {:Arellano2015 - Natural Language Processing of Textual Requirements.pdf:PDF},
but the PDF is not available/existing in the folder.

Switch to Tab File Annotations: NPE exception comes:

java.lang.NullPointerException: null
	at org.jabref.gui.entryeditor.FileAnnotationTab.updateShownAnnotations(FileAnnotationTab.java:130) ~[bin/:?]
	at org.jabref.gui.entryeditor.FileAnnotationTab.addAnnotations(FileAnnotationTab.java:114) ~[bin/:?]
	at org.jabref.gui.entryeditor.FileAnnotationTab.initializeTab(FileAnnotationTab.java:89) ~[bin/:?]
	at org.jabref.gui.entryeditor.EntryEditor$TabListener.lambda$0(EntryEditor.java:1155) ~[bin/:?]
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311) ~[?:1.8.0_121]