use Long.expand

Author: wenshao

src/java.base/share/classes/java/util/UUID.java

@@ -486,12 +486,7 @@ public String toString() {
     }
 
     private static void putHex8(byte[] bytes, int off, long i, boolean separator) {
-        // Long.expand(i, 0x0F0F_0F0F_0F0F_0F0FL)
-        long e = i & 0xF;
-        for (int x = 4; x < 64; x += 4) {
-            e |= ((i & (0xFL << x)) << x);
-        }
-
+        long e = Long.expand(i, 0x0F0F_0F0F_0F0F_0F0FL);
         /*
             Use long to simulate vector operations and generate 8 hexadecimal characters at a time.
             ------------