When I sent a "agent data" Json message with the payload

{"request":"agent data","data":[{"host":"new-host-3","key":"jmx-active[java.lang:type=OperatingSystem,FreePhysicalMemorySize]","value":"4013543424","clock":1361909453}],"clock":1361909453}

I receive the response:

{ "response":"success", "info":"Processed 1 Failed 0 Total 1 Seconds spent 0.000047"}

This message is processed correctly and the data appears in Zabbix server. Now I want to enclose the parameters "java.lang:type=OperatingSystem" and "FreePhysicalMemorySize" of the key in quotation marks because they might contain spaces. The corresponding payload is:

{"request":"agent data","data":[{"host":"new-host-3","key":"jmx-active[\"java.lang:type=OperatingSystem\",\"FreePhysicalMemorySize\"]","value":"4023709696","clock":1361909431}],"clock":1361909431}

Note that the quotation marks have to be escaped because they are contained in a Json string. When a message with this payload is sent to the server, then the following response is received:

{ "response":"success", "info":"Processed 0 Failed 1 Total 1 Seconds spent 0.000049"}

It seems that Zabbix server does not handle the escaped quotations marks in the key field correctly.