Create following discovery rule:

jmx.discovery[attributes]

Item prototype with key

jmx[{#JMXOBJ}, {#JMXATTR}]

Now discover attributes such as "s.i.m.p.l.e" (The app name) = My MBean name

Expected:
"s.i.m.p.l.e" MBean name works and discovered "s\.i\.m\.p\.l\.e"

Actual:
item "Zabbix server:jmx[com.example:type=Hello, s.i.m.p.l.e]" became not supported: getAttribute failed: ModelMBeanAttributeInfo not found for s