The init method for CounterService takes the Properties object as an argument. This means we can add properties to the service that are passed to the init method; see Creating the Service Class. You can add properties declaratively as shown below. (You likely want to name your properties something other than someproperty.)

<service enabled="true">

If you want to parse a more complex XML, you can use the interface com.hazelcast.spi.ServiceConfigurationParser. It gives you access to the XML DOM tree.