public boolean setupVault() {
        Plugin plugin = this.getServer().getPluginManager().getPlugin("Vault");
        if (plugin != null & plugin instanceof Vault) {
            RegisteredServiceProvider<Economy> economyProvider = getServer()
                    .getServicesManager().getRegistration(
                            net.milkbowl.vault.economy.Economy.class);
            // 経済概念のプラグインがロードされているかチェック
            if (economyProvider == null) {
                log.warning(logPrefix
                        + "Economy plugin NOT found. Disabled Vault plugin integration.");
                return false;
            }

            try {
                vault = (Vault) plugin;
                economy = economyProvider.getProvider();

                if (vault == null || economy == null) {
                    throw new NullPointerException();
                }
            } // 例外チェック
            catch (Exception e) {
                log.warning(logPrefix
                        + "Could NOT be hook to Vault plugin. Disabled Vault plugin integration.");
                return false;
            }

            // Success
            log.info(logPrefix + "Hooked to Vault plugin!");
            return true;
        } else {
            // Vaultが見つからなかった
            log.warning(logPrefix
                    + "Vault plugin was NOT found! Disabled Vault integration.");
            return false;
        }
    }