AnnotatorPlus returns 500 with NPE on every request

[jvendetti]

Affected: services.data.bioontology.org/annotatorplus (BioPortal production)
Deployed version: org.sifrproject:sifr-bioportal-annotator-proxy:0.1-SNAPSHOT

Reproduction

Via curl:

$ curl -sL -H "Authorization: apikey token=<YOUR_API_KEY>" \
    "https://services.data.bioontology.org/annotatorplus?text=probiotics"

Returns HTTP 500 with the following stack trace embedded in the response body:

java.lang.NullPointerException
    at java.base/java.io.Reader.<init>(Reader.java:167)
    at java.base/java.io.InputStreamReader.<init>(InputStreamReader.java:93)
    at org.sifrproject.util.RestfulRequest.streamAsString(RestfulRequest.java:60)
    at org.sifrproject.util.RestfulRequest.queryAnnotator(RestfulRequest.java:27)
    at org.sifrproject.servlet.AnnotatorServlet.doPost(AnnotatorServlet.java:175)
    at org.sifrproject.servlet.AnnotatorServlet.doGet(AnnotatorServlet.java:118)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:529)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:623)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
    at org.sifrproject.util.CharacterSetFilter.doFilter(CharacterSetFilter.java:24)

Via the UI: navigate to the AnnotatorPlus page, insert the sample text, and click "Get annotations". The Rails application displays: Problem getting annotations, please try again.

Diagnosis

The NPE is the visible symptom, not the root cause. Initial investigation suggests the proxy is hitting an upstream redirect (HTTPS → HTTP) that Java's HttpURLConnection refuses to follow by default, and the response-handling code in RestfulRequest.queryAnnotator doesn't tolerate the resulting state — it calls getErrorStream() on a 3xx response, which returns null, and streamAsString(null) then NPEs in the InputStreamReader constructor.

Relates to: ncbo/ontologies_api#217