Hello Caroline -
Here's how you parse this error message:
Error Posting to URL:
http://localhost:6080/arcgis/rest/services/Caroline/Schema1/FeatureServer/0/query
with parameters:
where=animal_sighted IN ('Wildebeest','Zebra','Thompson_Gazelle','Giraffe','Lion')
&outfields=animal_sighted,objectid&f=json.
java.io.IOException: {"error":{"code":400,"message":"Unable to complete operation.",
"details":["Unable to perform query operation."]}} at
com.esri.ges.transport.featureService.FeatureServiceOutboundTransport.validateResponse(FeatureServiceOutboundTransport.java:745)
Line 2: You are making a query on the locally hosted Schema1 feature service (found in the Caroline services folder)
Line 4: GeoEvnet is looking for an OBJECTID (feature row identifier) for the listed TRACKID values ('Wildebeest', 'Zebra', etc.)
Line 5: The query should return only the fields: animal_sighted and objectid in a JSON structure
Line 6: ArcGIS Server couldn't complete the query ... this is a generic error return code and message from Server
Line 8: Identifies the component, method, and line of code in the GeoEvent implementation which generated the exception
Since you cannot attach a debugger and look into the GeoEvent source code, your only option is to set DEBUG logging on the reported component and see if you can get some additional information.
In GeoEvent Manager, click Logs > Settings and enter com.esri.ges.transport.featureService.FeatureServiceOutboundTransport as the component for which you want the Logger to produce DEBUG messages:
Save the logging settings and send / simulate another event so that your GeoEvent Service will try again to add / update features. (I'm assuming that is what you are trying to do, based on the error message you posted.)
Check the karaf.log to see if you were able to capture any additional information. I find that opening the logfile using a text editor can be more useful than looking at log messages in the GeoEvent Manager's Logs viewer. You can find the karaf.log file here: C:\Program Files\ArcGIS\Server\GeoEvent\data\log
Check your ArcGIS Server logs. There may be some additional detail on why Server was not able to honor the request GeoEvent was making on the feature service's ...\query endpoint.
Try rebuilding the query yourself in the ArcGIS REST Services Directory:
You may need to play with your query some, like changing the WHERE clause to 1=1 to query for all records and/or changing the Out Fields to a * (so that all fields are retrieved).
Pay particular attention to the URL generated based on the query you construct using the HTML page. You can copy / paste the URL from the ArcGIS REST Services Directory page into a text editor and look through the parameters. I know, for example, that there was a rather obscure defect in the 10.3.1 release which would only manifest when configuring an ArcGIS Server site with Portal and using the ArcGIS Data Store (a specific configuration of PostGRE database). The outFields parameter was being constructed as outfields (little 'f') ... which was not compliant with the ArcGIS REST specification and queries GeoEvent was making to try and obtain OBJECTID values were failing. (This issue should be fixed in the upcoming 10.4 release...)
Hope this information helps -
RJ