Running the Spring Boot application with the following VM arguments will enable it to be connected using jconsole remotely, and the exposed CustomEndpoint JMX Bean can be accessed using monitoring and management tools such as jconsole, which is shipped with the JDK installation:

-Djavax.management.builder.initial=      
-Dcom.sun.management.jmxremote      
-Dcom.sun.management.jmxremote.port=8855      
-Dcom.sun.management.jmxremote.authenticate=false      
-Dcom.sun.management.jmxremote.ssl=false

Run jconsole with the following command:

$ jconsole

Making a remote process connected with it to <host>:8855 will list all the MBeans from the Spring Boot application under MBeans tab. When the Custom.get operation is executed from jconsole it will show the return from CustomEndpoint.get as expected, as shown in the following screenshot: