Stack trace [15:36:39 ERROR]: Packet encoding of packet ID 85 threw (skippable? false) java.lang.NullPointerException: Cannot invoke "it.unimi.dsi.fastutil.objects.ObjectArrayList.get (int)" because ...

ERROR: NullPointerException encountered while trying to adding String to Deque that is set to null. java.lang.NullPointerException INFO: Successful at adding String to Deque that is set to null ...

In case the SequenceSnapshotGenerator is used by e.g. a sequenceExists precondition having no schema name set, the SequenceSnapshotGenerator fails at line 235 with a NullPointerException: "Cannot ...

Then there’s the NullPointerException. Null pointer exception is an “exception” (error) that is particularly common when programming in Java.