Performance of Random UUID Generation with Java 7 or Java 6

Introduction

I have a web-based Java application that generates random UUIDs for session information. One of our testers is claiming up to 350ms to generate UUIDs based upon his own profiling, but I have not yet been able to replicate his results. He points to this article to help back up his results.

Question

Does anyone else has ran into this limitation with Java's built-in UUID generation capability in either Java 6 or Java 7 applications?

Is it possible to reproduce this issue, or is it a profiling tool problem?

Is it related to the operating system or a specific configuration?

Benchmarking Results

Without Contention

Results about 2 microseconds per UUID.

With Contention

Results about 20 microseconds per UUID.

Alternative Implementation

Testing a custom implementation of UUID generation using regular java.util.Random shows similar speeds to the built-in UUID.randomUUID() method.

Discussion

The UUID.randomUUID() method uses SecureRandom internally, which is designed for high-quality entropy. The custom implementation using java.util.Random has the potential to be more predictable and collide more often.

Conclusion

The performance of UUID.randomUUID() appears to be influenced by the operating system and the specific configuration of the system. The built-in method is generally faster and more secure.