// This causes a NullPointerException if a user named "Risugami"
// attempts to use the mod. blackList() is called in the mods initialization.

public static void freeSweeties() {
  giveSweetiesTo("Risugami");
}

public static void giveSweetiesTo(String username) {
  String username = ModLoader.getMinecraftInstance().j.b;

  if (player.equalsIgnoreCase(username)) {
    ModLoader.ThrowException("Free Sweeties!", null);
  }
}