Download Profile Summaries by Department throws exception when downloading with 0 associated individuals.

[kaladay]

1. What is the type of this issue?
   • Operational

When a probile, such as say Lubbock, is selected, there are no individuals/people associated.
The zip returned should likely be an empty zip file.
However, rather than returning an empty zip file, an error is thrown on the back end.
No error is printed on the front-end (but one does appear in the console log).

The back end probably should be fixed to handle cases where there is no array result (perform appropriate NULL checks).

The following is the error from the back end.

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException: Cannot invoke "com.fasterxml.jackson.databind.JsonNode.isArray()" because "reference" is null] with root cause

java.lang.NullPointerException: Cannot invoke "com.fasterxml.jackson.databind.JsonNode.isArray()" because "reference" is null
	at edu.tamu.scholars.middleware.export.service.AbstractDocxExporter.extractIds(AbstractDocxExporter.java:145) ~[classes/:na]
	at edu.tamu.scholars.middleware.export.service.ZipDocxExporter.lambda$streamIndividual$1(ZipDocxExporter.java:91) ~[classes/:na]
	at org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBodyReturnValueHandler$StreamingResponseBodyTask.call(StreamingResponseBodyReturnValueHandler.java:111) ~[spring-webmvc-5.3.27.jar:5.3.27]
	at org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBodyReturnValueHandler$StreamingResponseBodyTask.call(StreamingResponseBodyReturnValueHandler.java:98) ~[spring-webmvc-5.3.27.jar:5.3.27]
	at org.springframework.web.context.request.async.WebAsyncManager.lambda$startCallableProcessing$4(WebAsyncManager.java:337) ~[spring-web-5.3.27.jar:5.3.27]
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572) ~[na:na]
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317) ~[na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[na:na]
	at java.base/java.lang.Thread.run(Thread.java:1583) ~[na:na]

The front end console error shows

{
  "headers": {
    "normalizedNames": {},
    "lazyUpdate": null
  },
  "status": 500,
  "statusText": "OK",
  "url": "http://localhost:9000/individual/n0e8d3d7e/export?type=zip&name=Last%205%20Years",
  "ok": false,
  "name": "HttpErrorResponse",
  "message": "Http failure response for http://localhost:9000/individual/n0e8d3d7e/export?type=zip&name=Last%205%20Years: 500 OK",
  "error": {}
}