Das ist die AsyncMySQL Klasse

package de.fallenbreak.coinsapi.database.container;

import org.bukkit.Bukkit;

import java.sql.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.function.Consumer;

public class AsyncMySQL {

    private ExecutorService executor;
    private MySQL sql;

    public static boolean unconnected = false;

    public AsyncMySQL(final String host, final int port, final String user, final String password, final String database) {
        try {
            this.sql = new MySQL(host, port, user, password, database);
            this.executor = Executors.newCachedThreadPool();
            unconnected = false;
        } catch (final Exception e) {
            unconnected = true;
            System.out.println("Stopping server! Reason: MYSQL - Not connect");
            Bukkit.shutdown();
        }
    }

    public void update(final PreparedStatement statement) {
        this.executor.execute(() -> this.sql.queryUpdate(statement));
    }

    public void update(final String statement) {
        this.executor.execute(() -> this.sql.queryUpdate(statement));
    }

    // statement = PreparedStatement
    public void query(final PreparedStatement statement, final Consumer<ResultSet> consumer) {
        this.executor.execute(() -> {
            final ResultSet result = this.sql.query(statement);
            consumer.accept(result);
        });
    }

    // statement = String
    public void query(final String statement, final Consumer<ResultSet> consumer) {
        this.executor.execute(() -> {
            final ResultSet result = this.sql.query(statement);
            consumer.accept(result);
        });
    }

    public PreparedStatement prepare(final String query) {
        try {
            return this.sql.getConnection().prepareStatement(query);
        } catch (final SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    public MySQL getMySQL() {
        return this.sql;
    }

    @SuppressWarnings({"WeakerAccess", "SqlNoDataSourceInspection"})
    public static class MySQL {

        private final String host;
        private final String user;
        private final String password;
        private final String database;
        private final int port;

        private Connection conn;

        public MySQL(final String host, final int port, final String user, final String password, final String database) throws Exception {
            this.host = host;
            this.port = port;
            this.user = user;
            this.password = password;
            this.database = database;

            this.openConnection();
        }

        public void queryUpdate(final String query) {
            this.checkConnection();
            try (final PreparedStatement statement = this.conn.prepareStatement(query)) {
                this.queryUpdate(statement);
            } catch (final SQLException e) {
                e.printStackTrace();
            }
        }

        public void queryUpdate(final PreparedStatement statement) {
            this.checkConnection();
            try {
                try {
                    statement.executeUpdate();
                } catch (final SQLException e) {
                    e.printStackTrace();
                }
            } finally {

                try {
                    statement.close();
                } catch (final SQLException e) {
                    e.printStackTrace();
                }
            }
        }

        public ResultSet query(final String query) {
            this.checkConnection();
            try {
                return this.query(this.conn.prepareStatement(query));
            } catch (final SQLException e) {
                e.printStackTrace();
            }
            return null;
        }

        public ResultSet query(final PreparedStatement statement) {
            this.checkConnection();
            try {
                return statement.executeQuery();
            } catch (final SQLException e) {
                e.printStackTrace();
            }
            return null;
        }

        public void checkConnection() {
            try {
                if (this.conn == null || !this.conn.isValid(10) || this.conn.isClosed()) {
                    this.openConnection();
                }

            } catch (final Exception e) {
                e.printStackTrace();
            }
        }

        public Connection openConnection() throws Exception {
            Class.forName("com.mysql.jdbc.Driver");
            return this.conn = DriverManager.getConnection("jdbc:mysql://" + this.host + ":" + this.port + "/" + this.database + "?autoReconnect=true", this.user, this.password);
        }

        public Connection getConnection() {
            return this.conn;
        }

        public void closeConnection() {
            try {
                this.conn.close();
            } catch (final SQLException e) {
                e.printStackTrace();
            } finally {
                this.conn = null;
            }
        }

        public boolean isConnected() {
            final String CHECK_SQL_QUERY = "SELECT 1";
            boolean isConnected = false;
            try {
                final PreparedStatement statement = this.conn.prepareStatement(CHECK_SQL_QUERY);
                isConnected = true;
            } catch (final SQLException | NullPointerException ignored) {
            }
            return isConnected;
        }
    }
}