BAEL-5332-convert-byte-array-and-uuid (#11822)

Co-authored-by: tienvn4 <tienvn4@ghtk.co>

core-java-modules/core-java-8-2/src/main/java/com/baeldung/uuid/UuidHelper.java

@@ -0,0 +1,33 @@
+package com.baeldung.uuid;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.UUID;
+
+public class UuidHelper {
+
+    public static byte[] convertUUIDToBytes(UUID uuid) {
+        ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
+        bb.putLong(uuid.getMostSignificantBits());
+        bb.putLong(uuid.getLeastSignificantBits());
+        return bb.array();
+    }
+
+    public static UUID convertBytesToUUID(byte[] bytes) {
+        ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
+        long high = byteBuffer.getLong();
+        long low = byteBuffer.getLong();
+        return new UUID(high, low);
+    }
+
+    public static void main(String[] args) {
+        UUID uuid = UUID.randomUUID();
+        System.out.println("Original UUID: " + uuid);
+
+        byte[] bytes = convertUUIDToBytes(uuid);
+        System.out.println("Converted byte array: " + Arrays.toString(bytes));
+
+        UUID uuidNew = convertBytesToUUID(bytes);
+        System.out.println("Converted UUID: " + uuidNew);
+    }
+}