Add missing Javadoc tag.
diff --git a/src/main/java/org/apache/commons/text/numbers/DoubleFormat.java b/src/main/java/org/apache/commons/text/numbers/DoubleFormat.java
index e395a5a..5f2204a 100644
--- a/src/main/java/org/apache/commons/text/numbers/DoubleFormat.java
+++ b/src/main/java/org/apache/commons/text/numbers/DoubleFormat.java
@@ -667,6 +667,7 @@
         /**
          * Return a formatted representation of the given rounded decimal value to {@code dst}.
          * @param val value to format
+         * @return a formatted representation of the given rounded decimal value to {@code dst}.
          */
         protected abstract String applyFiniteInternal(ParsedDecimal val);
     }