Description
Describe the bug
A course XML with metadata cannot be imported back. It gives a null pointer exception:
java.lang.NullPointerException: null
at org.kitodo.production.model.bibliography.course.metadata.CountableMetadata.setStartValue(CountableMetadata.java:306)
at org.kitodo.production.model.bibliography.course.Course.processRecoveredMetadata(Course.java:385)
at org.kitodo.production.model.bibliography.course.Course.<init>(Course.java:311)
at org.kitodo.production.forms.CalendarForm.upload(CalendarForm.java:678)
The line that causes the error was introduced in PR #4924.