diff --git a/server/src/main/java/org/elasticsearch/index/mapper/NestedObjectMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/NestedObjectMapper.java
index 4f1cf4689c2d7..4bc633296a832 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/NestedObjectMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/NestedObjectMapper.java
@@ -450,23 +450,20 @@ public boolean hasValue() {
         @Override
         public void write(XContentBuilder b) throws IOException {
             assert (children != null && children.size() > 0);
-            switch (children.size()) {
-                case 1 -> {
-                    b.startObject(simpleName());
-                    leafStoredFieldLoader.advanceTo(children.get(0));
-                    leafSourceLoader.write(leafStoredFieldLoader, children.get(0), b);
+            if (children.size() == 1) {
+                b.startObject(simpleName());
+                leafStoredFieldLoader.advanceTo(children.get(0));
+                leafSourceLoader.write(leafStoredFieldLoader, children.get(0), b);
+                b.endObject();
+            } else {
+                b.startArray(simpleName());
+                for (int childId : children) {
+                    b.startObject();
+                    leafStoredFieldLoader.advanceTo(childId);
+                    leafSourceLoader.write(leafStoredFieldLoader, childId, b);
                     b.endObject();
                 }
-                default -> {
-                    b.startArray(simpleName());
-                    for (int childId : children) {
-                        b.startObject();
-                        leafStoredFieldLoader.advanceTo(childId);
-                        leafSourceLoader.write(leafStoredFieldLoader, childId, b);
-                        b.endObject();
-                    }
-                    b.endArray();
-                }
+                b.endArray();
             }
         }
 
diff --git a/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperServiceTestCase.java b/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperServiceTestCase.java
index 9531181013d56..0486022620398 100644
--- a/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperServiceTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperServiceTestCase.java
@@ -802,6 +802,7 @@ private void roundTripSyntheticSource(DocumentMapper mapper, String syntheticSou
         try (Directory roundTripDirectory = newDirectory()) {
             RandomIndexWriter roundTripIw = indexWriterForSyntheticSource(roundTripDirectory);
             ParsedDocument doc = mapper.parse(new SourceToParse("1", new BytesArray(syntheticSource), XContentType.JSON));
+            // Process root and nested documents in the same way as the normal indexing chain (assuming a single document)
             doc.updateSeqID(0, 0);
             doc.version().setLongValue(0);
             roundTripIw.addDocuments(doc.docs());