adam bien's blog

"In computing, a plug-in (or plugin) is a set of software components that adds specific abilities to a larger software application. If supported, plug-ins enable customizing the functionality of an application…"

public interface ConfigurationProvider {
    
    public Map<String,String> getConfiguration();

}

import javax.enterprise.inject.Instance;
import javax.inject.Inject;

@Startup
@Singleton
public class Configuration {

    private Map<String, String> configuration;

    @Inject
    private Instance<ConfigurationProvider> configurationProvider;

   @PostConstruct
    public void fetchConfiguration() {
        this.configuration = new HashMap<String, String>() {{
            put("version", "0.7");
			//...other defaults
        }};
        this.unconfiguredFields = new HashSet<String>();
        mergeWithCustomConfiguration();
    }
    //...

}