Efficient method to generate UUID String in Java (UUID.randomUUID().toString() without the dashes)

Performance Pitfall and Boost

Randomness and Security

You need to mind the security and randomness. The significant bits of UUID encode its version and variant — make sure they're undisturbed.

Performance Trade-off

If speed is your game, ThreadLocalRandom usually wins against SecureRandom. But, if you're dealing with delicate cryptographic usages, SecureRandom is your safe pick.

Custom UUID Brew

For a tailored UUID concoction, you can craft a custom algorithm bypassing the UUID's dash dilemma. It's like making your coffee — just the way you like it.

Custom UUID Generation

SecureRandom Method

SecureRandom random = new SecureRandom();
byte[] randomBytes = new byte[16];
random.nextBytes(randomBytes);

// This isn't a witch's brew, just brewing some UUID!
StringBuffer uuidBrew = new StringBuffer();
for (int i = 0; i < randomBytes.length; i++) {
    uuidBrew.append(String.format("%02x", randomBytes[i]));
}
String customUUID = uuidBrew.toString();
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Criss-crossing JVMs: JUG Library

For unique UUIDs across JVMs, JUG (Java UUID Generator) is a reliable tool. It's like a passport for your UUIDs, valid everywhere!

URL encoding: Not required

Reminding you, URLEncoder.encode() is great for transforming spaces into + but we don't need it for a dash-less UUID. It's like bringing a sword to a fistfight!

Trust Yes. But, Test First!

Testing Randomness and Uniqueness

Developing your own random generation logic? Test exhaustively! Randomness and uniqueness are the promises a UUID upholds, so make sure the oath is unbroken!

Leading Zeroes and Full Byte Representation

Stay alert for the sneaky edge cases like leading zeroes being chopped off unintentionally. A byte array dons an incomplete cape without its full hexadecimal representation!

To Dash or Not to Dash

Uniform Resource Locator: Not a Must

In HTTP requests, dashes need no eviction. But, your application might crave a clean alphanumeric string — serve it right!

Readability vs Performance: The Balance

Dashes enhance readability whereas dash-less UUIDs are more compact and efficient. However, remember, the balcony view is prettier but the elevator ride (UUID generation!) is the real time consumer.