Java UUID fromString()

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In this guide, you will learn about the UUID fromString() method in Java programming and how to use it with an example.

1. UUID fromString() Method Overview

Definition:

The fromString() method of the UUID class in Java is a static method that creates a UUID object from the specified string. The string must represent a UUID and be in the format of 8-4-4-4-12 hex digits, separated by dashes.

Syntax:

public static UUID fromString(String name)

Parameters:

- name: The string from which the UUID is to be created. It must be in the format of 8-4-4-4-12 hexadecimal digits, separated by dashes.

Key Points:

- The UUID class is part of the java.util package.

- The fromString() method throws IllegalArgumentException if the provided string does not conform to the specified format.

- It’s useful for converting a string representation of UUID back to a UUID object.

- The method is typically used when a UUID is serialized to a string using toString() method and later needs to be deserialized.

2. UUID fromString() Method Example

import java.util.UUID;

public class UUIDExample {
    public static void main(String[] args) {
        // The string representing the UUID
        String uuidString = "f47ac10b-58cc-4372-a567-0e02b2c3d479";

        // Creating a UUID object from the string
        UUID uuid = UUID.fromString(uuidString);

        // Printing the UUID object
        System.out.println("UUID from String: " + uuid);

        // Attempting to create a UUID from an invalid string
        try {
            UUID invalidUUID = UUID.fromString("invalid-uuid-string");
            System.out.println("Invalid UUID: " + invalidUUID);
        } catch (IllegalArgumentException e) {
            System.out.println("Exception: " + e.getMessage());
        }
    }
}

Output:

UUID from String: f47ac10b-58cc-4372-a567-0e02b2c3d479
Exception: Invalid UUID string: invalid-uuid-string

Explanation:

In this example, we successfully created a UUID object from a valid string representing a UUID and printed it. We also attempted to create a UUID from an invalid string, which resulted in an IllegalArgumentException, demonstrating that the input string must conform to the UUID format.