request a proper object from a jmx endpoint, for example :

jmx["java.lang:type=Memory","HeapMemoryUsage.used"]

only value is returned. request invalid one, for example :

jmx["java.lang:type=Memory","HeapMemoryUsage22.used"]

error is returned, but for some reason value is returned as well :

{
"data": [

{"value": "2205192"}

,

{"error": "No such attribute: HeapMemoryUsage22"}

],
"response": "success"
}