unable to suppress "/" in mbean, tried encoding and ! as well, using curl

i am trying to access one attribute for tomcat using curl, below are the details

required mbean and attribute are:

{"mbean":"catalina:context=/developer,host=localhost,type=Manager","attribute":"activesessions","type":"read"}

trying to retrieve attribute "activesessions" but failed as i am unable to suppress "/" in context.

options i tried and failed are

curl -u username:pasword http://HOST.com:9999/jolokia/read/catalina:context=/developer,host=localhost,type=Manager/activesessions 

curl -u username:pasword http://HOST.com:9999/jolokia/read/catalina:context=!/developer,host=localhost,type=Manager/activesessions 

unable to figure out what to do, can someone please help?

jolokia version is 1.2.3 and tomcat version is 8.5.16