private Object getRawHistogramOutput() {
        final MBeanServer server = ManagementFactory.getPlatformMBeanServer();
        Object output;
        try {
            final ObjectName objectName = new ObjectName(DIAGNOSTIC_COMMAND_MBEAN_OBJECT_NAME);
            output = server.invoke(
                    objectName,
                    ACTION_NAME,
                    new Object[]{null},
                    new String[]{String[].class.getName()});
        } catch (MalformedObjectNameException
                | InstanceNotFoundException
                | ReflectionException
                | MBeanException e) {
            throw new RuntimeException(LogUtil.message("Error invoking action {}", ACTION_NAME), e);
        }
        return output;
    }
Generates a heap histogram using the 'gcClassHistogram' MBean action.  Will
block until the action completes/fails.
list of {@link HeapHistogramEntry}
stroom-node/stroom-node-impl/src/main/java/stroom/node/impl/HeapHistogramService.java