diff --git a/common/unsafe/src/main/java/org/apache/spark/unsafe/types/ByteArray.java b/common/unsafe/src/main/java/org/apache/spark/unsafe/types/ByteArray.java
index 3ced2094f5e6b..a593c0325b13e 100644
--- a/common/unsafe/src/main/java/org/apache/spark/unsafe/types/ByteArray.java
+++ b/common/unsafe/src/main/java/org/apache/spark/unsafe/types/ByteArray.java
@@ -44,7 +44,7 @@ public static long getPrefix(byte[] bytes) {
       final int minLen = Math.min(bytes.length, 8);
       long p = 0;
       for (int i = 0; i < minLen; ++i) {
-        p |= (128L + Platform.getByte(bytes, Platform.BYTE_ARRAY_OFFSET + i))
+        p |= ((long)Platform.getByte(bytes, Platform.BYTE_ARRAY_OFFSET + i) & 0xff)
             << (56 - 8 * i);
       }
       return p;