[#5141] fixed latest instance information cannot be obtained when cache instances is empty problem. (#5142)

Author: chengyouling

.github/workflows/checkstyle.yml

@@ -26,7 +26,7 @@ on:
 jobs:
   checkstyle:
     timeout-minutes: 60
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v3
       - name: Set up jdk

.github/workflows/maven.yml

@@ -29,7 +29,7 @@ jobs:
   build:
 
     timeout-minutes: 60
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
 
     steps:
     - uses: actions/checkout@v3

.github/workflows/rat_check.yml

@@ -29,7 +29,7 @@ on:
 jobs:
   rat_check:
     timeout-minutes: 60
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v3
       - name: Set up jdk

.github/workflows/spotbugs.yml

@@ -26,7 +26,7 @@ on:
 jobs:
   spotbugs:
     timeout-minutes: 60
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v3
       - name: Set up jdk

.github/workflows/unit-test-jdk11.yml

@@ -27,7 +27,7 @@ on:
 jobs:
   unit-tests:
     timeout-minutes: 60
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v3
       - name: Set up jdk

.github/workflows/unit-test-jdk17.yml

@@ -27,7 +27,7 @@ on:
 jobs:
   unit-tests:
     timeout-minutes: 60
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v3
       - name: Set up jdk

clients/service-center-client/src/main/java/org/apache/servicecomb/service/center/client/ServiceCenterDiscovery.java

@@ -17,6 +17,7 @@
 
 package org.apache.servicecomb.service.center.client;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -296,9 +297,15 @@ public void execute() {
   }
 
   private synchronized void pullAllInstance() {
+    List<SubscriptionKey> emptyInstancesCache = new ArrayList<>();
     instancesCache.forEach((k, v) -> {
       pullInstance(k, v, true);
+      if (v.instancesCache.isEmpty()) {
+        emptyInstancesCache.add(k);
+      }
     });
+    emptyInstancesCache.forEach(instancesCache::remove);
+    emptyInstancesCache.clear();
   }
 
   private static String instanceToString(List<MicroserviceInstance> instances) {