fix NPE in WlsClusterConfig.getServerConfigs() when dynamicServerConfigs.getServerConfigs() returns null

Author: alai8

operator/src/main/java/oracle/kubernetes/operator/wlsconfig/WlsClusterConfig.java

@@ -7,6 +7,7 @@
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import javax.annotation.Nonnull;
 
 import oracle.kubernetes.utils.OperatorUtils;
@@ -226,9 +227,8 @@ public void setWlsDomainConfig(WlsDomainConfig wlsDomainConfig) {
   public synchronized List<WlsServerConfig> getServerConfigs() {
     int dcsize = dynamicServersConfig == null ? 0 : dynamicServersConfig.getDynamicClusterSize();
     List<WlsServerConfig> result = new ArrayList<>(dcsize + servers.size());
-    if (dynamicServersConfig != null) {
-      result.addAll(dynamicServersConfig.getServerConfigs());
-    }
+    Optional.ofNullable(dynamicServersConfig).map(WlsDynamicServersConfig::getServerConfigs)
+        .ifPresent(dynamicServers -> dynamicServers.forEach(item -> result.add(item)));
     result.addAll(servers);
     result.sort(Comparator.comparing((WlsServerConfig sc) -> OperatorUtils.getSortingString(sc.getName())));
     return result;

operator/src/test/java/oracle/kubernetes/operator/wlsconfig/WlsClusterConfigTest.java

@@ -195,6 +195,14 @@ void verifyGetServerConfigsReturnListOfAllServerConfigs() {
     assertTrue(containsServer(wlsClusterConfig, "ms-1"));
   }
 
+  @Test
+  void verifyGetServerConfigsReturnEmptyServerListForDynamicServersWithClusterSizeOf0() {
+    WlsClusterConfig wlsClusterConfig =
+        new WlsClusterConfig("cluster1", createDynamicServersConfig(0, 0, 0, "ms-", "cluster1"));
+
+    assertTrue(wlsClusterConfig.getServerConfigs().isEmpty());
+  }
+
   @Test
   void verifyGetServerConfigsReturnListOfAllServerConfigsWithDynamicServers() {
     WlsClusterConfig wlsClusterConfig =