private boolean checkGroupExists(String group) {
        return this.plugin.getGroupManager().getByDisplayName(group) != null;
    }
An implementation of the Vault {@link Permission} API using LuckPerms.

LuckPerms is a multithreaded permissions plugin, and some actions require considerable
time to execute. (database queries, re-population of caches, etc) In these cases, the
operations required to make the edit apply will be processed immediately, but the process
of saving the change to the plugin storage will happen in the background.

Methods that have to query data from the database will throw exceptions when called
from the main thread. Users of the Vault API expect these methods to be "main thread friendly",
which they simply cannot be, as LP utilises databases for data storage. Server admins
willing to take the risk of lagging their server can disable these exceptions in the config file.
bukkit/src/main/java/me/lucko/luckperms/bukkit/vault/LuckPermsVaultPermission.java