ggdio · July 30, 2019 01:27 · Jul 30, 2019
diff --git a/ConcurrentUUIDGenerator.java b/ConcurrentUUIDGenerator.java
@@ -0,0 +1,20 @@
+public class ConcurrentUUIDGenerator {
+
+  public static UUID randomUUID() {
+        final Random rnd = ThreadLocalRandom.current();
+        long mostSig  = rnd.nextLong();
+        long leastSig = rnd.nextLong();
+
+        // Identify this as a version 4 UUID, that is one based on a random value.
+        mostSig &= 0xffffffffffff0fffL;
+        mostSig |= 0x0000000000004000L;
+
+        // Set the variant identifier as specified for version 4 UUID values.  The two
+        // high order bits of the lower word are required to be one and zero, respectively.
+        leastSig &= 0x3fffffffffffffffL;
+        leastSig |= 0x8000000000000000L;
+
+        return new UUID(mostSig, leastSig);
+    }
+
+}