diff --git a/java_gen/templates/of_class.java b/java_gen/templates/of_class.java
index ef927fd..46dc1ea 100644
--- a/java_gen/templates/of_class.java
+++ b/java_gen/templates/of_class.java
@@ -327,10 +327,13 @@
 //:: if not msg.is_fixed_length:
             // update length field
             int length = bb.writerIndex() - startIndex;
-            bb.setShort(lengthIndex, length);
+            //:: if msg.align:
+            int alignedLength = ((length + ${msg.align-1})/${msg.align} * ${msg.align});
+            //:: #endif
+            bb.setShort(lengthIndex, ${"alignedLength" if msg.length_includes_align else "length"});
             //:: if msg.align:
             // align message to ${msg.align} bytes
-            bb.writeZero( ((length + ${msg.align-1})/${msg.align} * ${msg.align}) - length);
+            bb.writeZero(alignedLength - length);
             //:: #endif
 //:: #end