Fixed BinaryData.compareBytes to treat bytes as unsigned

This is a regression fix introudeced in 1.12.1
added unit test

Author: jasonf20

lang/java/avro/src/main/java/org/apache/avro/io/BinaryData.java

@@ -181,10 +181,10 @@ private static int compare(Decoders d, Schema schema) throws IOException {
 
   /**
    * Lexicographically compare bytes. If equal, return zero. If greater-than,
-   * return a positive value, if less than return a negative value.
+   * return a positive value, if less than, return a negative value.
    */
   public static int compareBytes(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
-    return Arrays.compare(b1, s1, s1 + l1, b2, s2, s2 + l2);
+    return Arrays.compareUnsigned(b1, s1, s1 + l1, b2, s2, s2 + l2);
   }
 
   private static class HashData {

lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryData.java

@@ -18,10 +18,11 @@
 
 package org.apache.avro.io;
 
+import org.junit.jupiter.api.Test;
+
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class TestBinaryData {
 
@@ -60,4 +61,34 @@ void testIntLongVleEquality() {
     BinaryData.encodeLong(Integer.MIN_VALUE, longResult, 0);
     assertArrayEquals(intResult, longResult);
   }
+
+  @Test
+  void testCompareBytesUnsigned() {
+    // Test case: byte value 0xFF (-1 as signed, 255 as unsigned)
+    // should be greater than 0x7F (127)
+    byte[] b1 = new byte[] { (byte) 0xFF };
+    byte[] b2 = new byte[] { (byte) 0x7F };
+    int result = BinaryData.compareBytes(b1, 0, 1, b2, 0, 1);
+    assertTrue(result > 0, "0xFF (255 unsigned) should be greater than 0x7F (127)");
+    result = BinaryData.compareBytes(b2, 0, 1, b1, 0, 1);
+    assertTrue(result < 0, "0x7F (127) should be less than 0xFF (255 unsigned)");
+    result = BinaryData.compareBytes(b1, 0, 1, b1, 0, 1);
+    assertEquals(0, result, "Equal byte arrays should return 0");
+
+    // Test with multiple bytes: {0x00, 0xFF} vs {0x00, 0x7F}
+    byte[] b3 = new byte[] { 0x00, (byte) 0xFF };
+    byte[] b4 = new byte[] { 0x00, (byte) 0x7F };
+    byte[] b5 = new byte[] { (byte) 0xFF, 0x00 };
+    byte[] b6 = new byte[] { (byte) 0x7F, 0x00 };
+    result = BinaryData.compareBytes(b3, 0, 2, b4, 0, 2);
+    assertTrue(result > 1, "{0x00, 0xFF} should be greater than {0x00, 0x7F}");
+    result = BinaryData.compareBytes(b5, 0, 2, b6, 0, 2);
+    assertTrue(result > 1, "{0xFF, 0x00} should be greater than {0x7F, 0x00}");
+
+    // Test with negative byte values: -1 (0xFF) should be greater than -128 (0x80)
+    byte[] b7 = new byte[] { (byte) -1 };
+    byte[] b8 = new byte[] { (byte) -128 };
+    result = BinaryData.compareBytes(b7, 0, 1, b8, 0, 1);
+    assertTrue(result > 0, "-1 (0xFF=255 unsigned) should be greater than -128 (0x80=128 unsigned)");
+  }
 }