Revert "Let list handling catch up with Java 17"

2 files changed, 6 insertions, 4 deletions

diff --git a/container-core/src/main/java/com/yahoo/component/chain/Chain.java b/container-core/src/main/java/com/yahoo/component/chain/Chain.java
index 24c4a0a0e2e..e44eba35efe 100644
--- a/container-core/src/main/java/com/yahoo/component/chain/Chain.java
+++ b/container-core/src/main/java/com/yahoo/component/chain/Chain.java
@@ -1,6 +1,7 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.component.chain;
 
+import com.google.common.collect.ImmutableList;
 import com.yahoo.component.ComponentId;
 import com.yahoo.component.chain.dependencies.ordering.ChainBuilder;
 
@@ -27,7 +28,7 @@ public class Chain<COMPONENT extends ChainedComponent> {
     /** Create a chain directly. This will NOT order the chain by the ordering constraints. */
     public Chain(ComponentId id, List<COMPONENT> componentList) {
         this.id = id;
-        this.componentList = List.copyOf(componentList);
+        this.componentList = ImmutableList.copyOf(componentList);
     }
 
     /** Create a chain directly. This will NOT order the chain by the ordering constraints. */
diff --git a/container-core/src/main/java/com/yahoo/processing/handler/ProcessingResponse.java b/container-core/src/main/java/com/yahoo/processing/handler/ProcessingResponse.java
index 959caa215be..28645b4bde0 100644
--- a/container-core/src/main/java/com/yahoo/processing/handler/ProcessingResponse.java
+++ b/container-core/src/main/java/com/yahoo/processing/handler/ProcessingResponse.java
@@ -1,6 +1,7 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.processing.handler;
 
+import com.google.common.collect.ImmutableList;
 import com.yahoo.container.jdisc.AsyncHttpResponse;
 import com.yahoo.container.jdisc.VespaHeaders;
 import com.yahoo.jdisc.handler.CompletionHandler;
@@ -109,13 +110,13 @@ public class ProcessingResponse extends AsyncHttpResponse {
 
     private List<ErrorMessage> flattenErrors(Response processingResponse) {
         Set<ErrorMessage> errors = flattenErrors(null, processingResponse.data());
-        if (errors == null) return List.of();
-        return List.copyOf(errors);
+        if (errors == null) return Collections.emptyList();
+        return ImmutableList.copyOf(errors);
     }
 
     @SuppressWarnings("unchecked")
     private Set<ErrorMessage> flattenErrors(Set<ErrorMessage> errors, Data data) {
-        if (data.request() == null) return Set.of(); // Not allowed, but handle anyway
+        if (data.request() == null) return Collections.EMPTY_SET; // Not allowed, but handle anyway
         errors = addTo(errors, data.request().errors());
 
         if (data instanceof DataList) {