jhy/jsoup · error · IllegalArgumentException

You must execute the request before getting a response.

Error message

You must execute the request before getting a response.

What it means

HttpConnection.Response is only populated after Connection.execute() (or get()/post()) completes. Calling response() on the Connection before executing throws this IllegalArgumentException because the internal `res` field is still null. It guards against reading a response that does not exist yet.

Solutions

1. Call Connection.execute() (or get()/post()) before response()
2. Use conn.execute().response() chained form so ordering is enforced
3. Prefer Jsoup.connect(url).execute() and hold the returned Response directly

Example fix

// before
Connection conn = Jsoup.connect(url);
Document doc = conn.response().parse();
// after
Connection.Response res = Jsoup.connect(url).execute();
Document doc = res.parse();

if (connection instanceof HttpConnection) { /* prefer tracking your own executed flag */ }

try { return conn.response(); } catch (IllegalArgumentException e) { return conn.execute(); }

When it happens

Trigger: Calling conn.response() after Jsoup.connect(url) but before conn.execute(); calling response() on a freshly built Connection; chaining that reads response before execute().

Common situations: Refactoring from one-shot Jsoup.connect(...).get() to multi-step execute()/response() flows; forgetting that response() is a getter on Connection, not an executor; reading response in a finally block before execute succeeded.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• URL not set. Make sure to call #url(...) before executing…
• Cannot follow redirect with a streamed request body…
• HTTP error fetching URL
• Unhandled content type. Must be a text or XML media type
• Too many redirects occurred trying to load URL

AI-assisted analysis of jhy/jsoup@9851ac5d9c (2026-09-08). Data as JSON: /api/errors/ac0886010c6d3a4b. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/org/jsoup/helper/HttpConnection.java:383

        res = Response.execute(req);
        return res;
    }

    @Override
    public Connection.Request request() {
        return req;
    }

    @Override
    public Connection request(Connection.Request request) {
        req = (HttpConnection.Request) request; // will throw a class-cast exception if the user has extended some but not all of Connection; that's desired
        return this;
    }

    @Override
    public Connection.Response response() {
        if (res == null) {
            throw new IllegalArgumentException("You must execute the request before getting a response.");
        }
        return res;
    }

    @Override
    public Connection response(Connection.Response response) {
        res = response;
        return this;
    }

    @Override
    public Connection postDataCharset(String charset) {
        req.postDataCharset(charset);
        return this;
    }

    @Override public Connection auth(@Nullable RequestAuthenticator authenticator) {
        req.auth(authenticator);

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