The same problem is in this (CLOSED) issue https://support.zabbix.com/browse/ZBX-12705. But we need name of datasource for better readable in item. We found another problems with this “-“ pattern in other JMX path, this little change solved everything. This fix replace problem paterns.
 
Symptoms:
V3.4.0-V3.4.4 Java Gateway

[ root @ tst-monit-001 ~ ] # ./zabbix_get_jmx.sh 'jmx.discovery[beans,"jboss.as:subsystem=datasources,data-source=*,statistics=pool"]' | jq '.data[0].value | fromjson | .data'

Output:

[
  {
    "{#JMXDOMAIN}": "jboss.as",
    "{#JMXDATA-SOURCE}": "NAV_DS",
    "{#JMXSUBSYSTEM}": "datasources",
    "{#JMXSTATISTICS}": "pool",
    "{#JMXOBJ}": "jboss.as:subsystem=datasources,data-source=NAV_DS,statistics=pool"
  }

This is exactly the same problem like in the issue.
 
V3.4.5+ Java Gateway
[ root @ tst-monit-001 ~ ] # ./zabbix_get_jmx.sh 'jmx.discovery[beans,"jboss.as:subsystem=datasources,data-source=*,statistics=pool"]' | jq '.data[0].value | fromjson | .data'
[
  {
    "{#JMXDOMAIN}": “jboss.as",
    "{#JMXSUBSYSTEM}": "datasources",
    "{#JMXSTATISTICS}": "pool",
    "{#JMXOBJ}": "jboss.as:subsystem=datasources,data-source=NAV_DS,statistics=pool"
  },
 
As you can see there is no possibility to read name of Datasource. I can only use {#JMXOBJ} to name it.
 
My version is (recompiled 3.4.9)

*What I change in this file is: ** *JMXItemChecker.java

274 // This is changed for replace special characters
275 //String key = property.getKey().toUpperCase();
276 String key = property.getKey().toUpperCase().replace('-', '_’);
 
Result:

[ root @ tst-monit-001 ~ ] # ./zabbix_get_jmx.sh 'jmx.discovery[beans,"jboss.as:subsystem=datasources,data-source=*,statistics=pool"]' | jq '.data[0].value | fromjson | .data'

Output:

[
  {
    "{#JMXDOMAIN}": "jboss.as",
    "{#JMXDATA_SOURCE}": "NAV_DS",
    "{#JMXSUBSYSTEM}": "datasources",
    "{#JMXSTATISTICS}": "pool",
    "{#JMXOBJ}": "jboss.as:subsystem=datasources,data-source=NAV_DS,statistics=pool"
  }

{#JMXDATA_SOURCE} is valid for zabbix macros

 
I attached screenshoots from zabbix. There is a difference between name of datasource as you can see .