Escape `.` in `String.replaceFirst` as it acts as a wildcard (#7576)

oap-server/server-configuration/configuration-k8s-configmap/src/main/java/org/apache/skywalking/oap/server/configuration/configmap/ConfigmapConfigurationWatcherRegister.java

@@ -59,8 +59,8 @@ public class ConfigmapConfigurationWatcherRegister extends ConfigWatcherRegister
             GroupConfigTable.GroupConfigItems groupConfigItems = new GroupConfigTable.GroupConfigItems(key);
             groupConfigTable.addGroupConfigItems(groupConfigItems);
             configMapData.forEach((groupItemKey, itemValue) -> {
-                if (groupItemKey.startsWith(key)) {
-                    String itemName = groupItemKey.replaceFirst(key + ".", "");
+                if (groupItemKey.startsWith(key + ".")) {
+                    String itemName = groupItemKey.substring(key.length() + 1);
                     groupConfigItems.add(new ConfigTable.ConfigItem(itemName, itemValue));
                 }
             });

oap-server/server-configuration/configuration-k8s-configmap/src/main/java/org/apache/skywalking/oap/server/configuration/configmap/ConfigurationConfigmapInformer.java

@@ -29,6 +29,7 @@ import io.kubernetes.client.openapi.models.V1ConfigMapList;
 import io.kubernetes.client.util.Config;
 import java.io.IOException;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.ExecutorService;
@@ -86,14 +87,17 @@ public class ConfigurationConfigmapInformer {
 
     public Map<String, String> configMapData() {
         Map<String, String> configMapData = new HashMap<>();
-        if (configMapLister != null && configMapLister.list() != null) {
-            configMapLister.list().forEach(cf -> {
-                Map<String, String> data = cf.getData();
-                if (data == null) {
-                    return;
-                }
-                configMapData.putAll(data);
-            });
+        if (configMapLister != null) {
+            final List<V1ConfigMap> list = configMapLister.list();
+            if (list != null) {
+                list.forEach(cf -> {
+                    Map<String, String> data = cf.getData();
+                    if (data == null) {
+                        return;
+                    }
+                    configMapData.putAll(data);
+                });
+            }
         }
 
         return configMapData;