HMCL-dev/HMCL · error · IllegalArgumentException

Profile name cannot be blank

Error message

Profile name cannot be blank

What it means

OfflineAccount's constructor throws IllegalArgumentException when the given profile (character) name is null-blank. HMCL requires every offline account to carry a non-blank profile name because it is used to derive the profile UUID and identify the character in game.

Solutions

1. Pass a non-blank profile name when creating the OfflineAccount (trim the user input first).
2. Validate the name with StringUtils.isBlank(name) before constructing the account and show a user-facing prompt.
3. If loading from storage, fall back to the account UUID string or a placeholder name instead of an empty value.

Example fix

// before
OfflineAccount acc = new OfflineAccount(downloader, name, UUID.nameUUIDFromBytes(name.getBytes()), null);
// after
String trimmed = name == null ? "" : name.trim();
if (trimmed.isEmpty()) throw new IllegalArgumentException("Please enter a character name");
OfflineAccount acc = new OfflineAccount(downloader, trimmed, UUID.nameUUIDFromBytes(trimmed.getBytes()), null);

if (name == null || name.trim().isEmpty()) {
    throw new IllegalArgumentException("Character name must not be blank");
}
OfflineAccount acc = new OfflineAccount(downloader, name.trim(), profileID, skin);

try {
    account = new OfflineAccount(downloader, name, profileID, skin);
} catch (IllegalArgumentException e) {
    // prompt the user to enter a valid character name
}

When it happens

Trigger: Calling new OfflineAccount(downloader, "", profileID, skin) or with a whitespace-only profileName; also constructing indirectly via OfflineAccountFactory.create(accountId, name) with an empty name string.

Common situations: Programmatic account creation from scripts or launch configs where the character name field is empty; migrated/edited accounts.json where a whitespace-only name slipped in; UI bypass tools that skip name validation.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Theme-pack asset entry is empty
• accountID is missing
• acTL chunk length must be
• /assets/
• authlib-injectors.json -> urls cannot be null.

AI-assisted analysis of HMCL-dev/HMCL@24702dc5a0 (2026-09-10). Data as JSON: /api/errors/fc35f37b475cf389. Report an issue: GitHub.

Appendix: source

Thrown at HMCLCore/src/main/java/org/jackhuang/hmcl/auth/offline/OfflineAccount.java:72

    private final AuthlibInjectorArtifactProvider downloader;
    private final String profileName;
    private final UUID profileID;
    private Skin skin;

    protected OfflineAccount(
            AccountID accountID,
            AuthlibInjectorArtifactProvider downloader,
            String profileName,
            UUID profileID,
            Skin skin) {
        super(accountID);
        this.downloader = requireNonNull(downloader);
        this.profileName = requireNonNull(profileName);
        this.profileID = requireNonNull(profileID);
        this.skin = skin;

        if (StringUtils.isBlank(profileName)) {
            throw new IllegalArgumentException("Profile name cannot be blank");
        }
    }

    public AuthlibInjectorArtifactProvider getDownloader() {
        return downloader;
    }

    @Override
    public UUID getProfileID() {
        return profileID;
    }

    @Override
    public String getProfileName() {
        return profileName;
    }

    public Skin getSkin() {

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