java.util.UUID.fromString not checking length

Question

When I looked into the implementation of java.util.UUID.fromString, I found that it doesn\'t check for the UUID length. Is there any particular reason for this?

Answer 1

Make sure to test against id.equalsIgnoreCase(parsed.toString()) because UUID.fromString(id) returns lower case even if you pass id as upper case.

@Component
public class UuidDtoValidator {

    public boolean isValidUuid(String id) {
        if (isBlank(id)) {
            return false;
        }

        try {
            UUID parsed = UUID.fromString(id);
            if (parsed.equals(new UUID(0, 0))) {
                return false;
            }
            return id.equalsIgnoreCase(parsed.toString());
        } catch (IllegalArgumentException e) {
            return false;
        }
    }
}