diff --git a/java/src/main/java/com/google/protobuf/micro/CodedOutputStreamMicro.java b/java/src/main/java/com/google/protobuf/micro/CodedOutputStreamMicro.java
index 0cb0774..dd722ba 100644
--- a/java/src/main/java/com/google/protobuf/micro/CodedOutputStreamMicro.java
+++ b/java/src/main/java/com/google/protobuf/micro/CodedOutputStreamMicro.java
@@ -674,7 +674,7 @@
    * {@code group} field.
    */
   public static int computeGroupSizeNoTag(final MessageMicro value) {
-    return value.getCachedSize();
+    return value.getSerializedSize();
   }
 
   /**
@@ -682,7 +682,7 @@
    * message field.
    */
   public static int computeMessageSizeNoTag(final MessageMicro value) {
-    final int size = value.getCachedSize();
+    final int size = value.getSerializedSize();
     return computeRawVarint32Size(size) + size;
   }