From eba2337e82a1b2cd355b6355b690034ee60aa332 Mon Sep 17 00:00:00 2001
From: David <dmollitor@apache.org>
Date: Tue, 24 Sep 2024 21:27:23 -0400
Subject: [PATCH] AVRO-4060: Use JDK to Hash Byte Array in UTF8

---
 .../avro/src/main/java/org/apache/avro/util/Utf8.java  | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java
index b38d237f212..b7d88bfc3db 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java
@@ -174,8 +174,14 @@ public int hashCode() {
     if (h == 0) {
       byte[] bytes = this.bytes;
       int length = this.length;
-      for (int i = 0; i < length; i++) {
-        h = h * 31 + bytes[i];
+      // If the array is filled, use the underlying JDK hash functionality.
+      // Starting with JDK 21, the underlying implementation is vectorized.
+      if (bytes.length == length) {
+        h = Arrays.hashCode(bytes);
+      } else {
+        for (int i = 0; i < length; i++) {
+          h = h * 31 + bytes[i];
+        }
       }
       this.hash = h;
     }