class Foo {
    private static Foo _instance;

    public static void initializeInstance(Context context) { // This is thread safe in real-world
        // runs heavy stuff
    }

    public static Foo getInstance(Context context) {
        if (_instance == null) {
            throw new IllegalStateException("not initialized");
        }
        return _instance;
    }
}

// Usage:
class App {
    public void entryPoint() {
        Foo.inititalizeInstance(context); // in real world this runs async
    }
}