Extract getApplications method in CommonsInstanceDiscovery

spring-cloud-netflix-turbine/src/main/java/org/springframework/cloud/netflix/turbine/CommonsInstanceDiscovery.java

@@ -95,7 +95,7 @@ public class CommonsInstanceDiscovery implements InstanceDiscovery {
 	@Override
 	public Collection<Instance> getInstanceList() throws Exception {
 		List<Instance> instances = new ArrayList<>();
-		List<String> appNames = getTurbineProperties().getAppConfigList();
+		List<String> appNames = getApplications();
 		if (appNames == null || appNames.size() == 0) {
 			log.info("No apps configured, returning an empty instance list");
 			return instances;
@@ -120,6 +120,10 @@ public class CommonsInstanceDiscovery implements InstanceDiscovery {
 		return instances;
 	}
 
+	protected List<String> getApplications() {
+		return turbineProperties.getAppConfigList();
+	}
+
 	/**
 	 * helper that fetches the Instances for each application from DiscoveryClient.
 	 * @param serviceId