diff --git a/java/core/src/main/java/com/google/protobuf/MessageSchema.java b/java/core/src/main/java/com/google/protobuf/MessageSchema.java
index 084d687d1a..ae5dddc53b 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageSchema.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageSchema.java
@@ -5510,6 +5510,12 @@ final class MessageSchema<T> implements Schema<T> {
             getMessageFieldSchema(pos).makeImmutable(UNSAFE.getObject(message, offset));
           }
           break;
+        case 60: // ONEOF_MESSAGE
+        case 68: // ONEOF_GROUP
+          if (isOneofPresent(message, numberAt(pos), pos)) {
+            getMessageFieldSchema(pos).makeImmutable(UNSAFE.getObject(message, offset));
+          }
+          break;
         case 18: // DOUBLE_LIST:
         case 19: // FLOAT_LIST:
         case 20: // INT64_LIST:
diff --git a/java/lite/src/test/java/com/google/protobuf/LiteTest.java b/java/lite/src/test/java/com/google/protobuf/LiteTest.java
index a4f95a2666..a58ce95df0 100644
--- a/java/lite/src/test/java/com/google/protobuf/LiteTest.java
+++ b/java/lite/src/test/java/com/google/protobuf/LiteTest.java
@@ -190,6 +190,18 @@ public class LiteTest {
     }
   }
 
+  @Test
+  public void testParsedOneofSubMessageIsImmutable() throws InvalidProtocolBufferException {
+    TestAllTypesLite message =
+        TestAllTypesLite.parseFrom(
+            TestAllTypesLite.newBuilder()
+                .setOneofNestedMessage(NestedMessage.newBuilder().addDd(1234).build())
+                .build()
+                .toByteArray());
+    IntArrayList subList = (IntArrayList) message.getOneofNestedMessage().getDdList();
+    assertThat(subList.isModifiable()).isFalse();
+  }
+
   @Test
   public void testMemoization() throws Exception {
     GeneratedMessageLite<?, ?> message = TestUtilLite.getAllLiteExtensionsSet();
@@ -2365,8 +2377,7 @@ public class LiteTest {
     Foo fooWithOnlyValue = Foo.newBuilder().setValue(1).build();
 
     Foo fooWithValueAndExtension =
-        fooWithOnlyValue
-            .toBuilder()
+        fooWithOnlyValue.toBuilder()
             .setValue(1)
             .setExtension(Bar.fooExt, Bar.newBuilder().setName("name").build())
             .build();
@@ -2382,8 +2393,7 @@ public class LiteTest {
     Foo fooWithOnlyValue = Foo.newBuilder().setValue(1).build();
 
     Foo fooWithValueAndExtension =
-        fooWithOnlyValue
-            .toBuilder()
+        fooWithOnlyValue.toBuilder()
             .setValue(1)
             .setExtension(Bar.fooExt, Bar.newBuilder().setName("name").build())
             .build();
@@ -2515,9 +2525,9 @@ public class LiteTest {
       assertWithMessage("expected exception").fail();
     } catch (InvalidProtocolBufferException expected) {
       assertThat(
-          TestAllExtensionsLite.newBuilder()
-              .setExtension(UnittestLite.optionalInt32ExtensionLite, 123)
-              .build())
+              TestAllExtensionsLite.newBuilder()
+                  .setExtension(UnittestLite.optionalInt32ExtensionLite, 123)
+                  .build())
           .isEqualTo(expected.getUnfinishedMessage());
     }
   }
diff --git a/src/google/protobuf/unittest_lite.proto b/src/google/protobuf/unittest_lite.proto
index 010d4a9c0b..e2730c6419 100644
--- a/src/google/protobuf/unittest_lite.proto
+++ b/src/google/protobuf/unittest_lite.proto
@@ -47,6 +47,7 @@ message TestAllTypesLite {
   message NestedMessage {
     optional int32 bb = 1;
     optional int64 cc = 2;
+    repeated int32 dd = 3 [packed = true];
   }
 
   message NestedMessage2 {