Merge pull request #698 from powerYao/master

apollo-configservice/src/main/java/com/ctrip/framework/apollo/metaservice/service/DiscoveryService.java

@@ -9,7 +9,7 @@ import com.netflix.discovery.shared.Application;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
-import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 @Service
@@ -23,7 +23,7 @@ public class DiscoveryService {
     if (application == null) {
       Tracer.logEvent("Apollo.EurekaDiscovery.NotFound", ServiceNameConsts.APOLLO_CONFIGSERVICE);
     }
-    return application != null ? application.getInstances() : new ArrayList<>();
+    return application != null ? application.getInstances() : Collections.emptyList();
   }
 
   public List<InstanceInfo> getMetaServiceInstances() {
@@ -31,7 +31,7 @@ public class DiscoveryService {
     if (application == null) {
       Tracer.logEvent("Apollo.EurekaDiscovery.NotFound", ServiceNameConsts.APOLLO_METASERVICE);
     }
-    return application != null ? application.getInstances() : new ArrayList<>();
+    return application != null ? application.getInstances() : Collections.emptyList();
   }
 
   public List<InstanceInfo> getAdminServiceInstances() {
@@ -39,6 +39,6 @@ public class DiscoveryService {
     if (application == null) {
       Tracer.logEvent("Apollo.EurekaDiscovery.NotFound", ServiceNameConsts.APOLLO_ADMINSERVICE);
     }
-    return application != null ? application.getInstances() : new ArrayList<>();
+    return application != null ? application.getInstances() : Collections.emptyList();
   }
 }