make copy of AdminServerSpec environment variable list before adding more vars

Author: alai8

operator/src/main/java/oracle/kubernetes/operator/helpers/JobHelper.java

@@ -11,6 +11,7 @@
 import io.kubernetes.client.models.V1PodList;
 import io.kubernetes.client.models.V1Volume;
 import io.kubernetes.client.models.V1VolumeMount;
+import java.util.ArrayList;
 import java.util.List;
 import oracle.kubernetes.operator.JobWatcher;
 import oracle.kubernetes.operator.LabelConstants;
@@ -93,7 +94,8 @@ protected List<V1VolumeMount> getAdditionalVolumeMounts() {
     @Override
     List<V1EnvVar> getConfiguredEnvVars(TuningParameters tuningParameters) {
       // Pod for introspector job would use same environment variables as for admin server
-      List<V1EnvVar> vars = getDomain().getAdminServerSpec().getEnvironmentVariables();
+      List<V1EnvVar> vars =
+          new ArrayList<>(getDomain().getAdminServerSpec().getEnvironmentVariables());
 
       addEnvVar(vars, "NAMESPACE", getNamespace());
       addEnvVar(vars, "DOMAIN_UID", getDomainUID());