CheckConnectionEvent

Gets fired when we’re checking whether the user is online or not. It carries no fields, since it’s a signal, not a data payload.

When it fires

CheckConnectionEvent fires immediately before Minified calls NetworkUtil.ensureOnline(...) internally. You’ll see it twice during a typical online launch:

1. Once at the very start of Launcher.launchMinecraft(), before anything else happens. The result decides whether the rest of the launch runs online (Forge/NeoForge installation, live version metadata, downloading the client jar) or falls back to offline mode.
2. Once inside ClientDownloader.downloadClient(), right before it tries to download the client JAR. This only runs standalone if you call ClientDownloader directly with a LaunchContext.

The connectivity check itself (DNS lookup, a raw TCP probe, and an HTTPS HEAD request) is not part of this event. CheckConnectionEvent only marks that the check is about to happen, which is useful for showing a “Checking connection…” indicator in your UI.

Right after this event, exactly one of two things happens:

• the check succeeds and the launch continues normally, or
• the check fails and OfflineEvent fires instead.

Java

eventBus.subscribe(CheckConnectionEvent.class, event -> {
    System.out.println("Checking your connection...");
});

Kotlin

eventBus.subscribe(CheckConnectionEvent::class.java) {
    println("Checking your connection...")
}