java - Connection error with MySQL; No Access

I've a problem with connecting to MySQL, i seeked at Google and this Website, and there are solutions for the problem, but they don't work in my code.

That's the code:

public static String host = SQL.getInstance().getConfig().getString("Config.SQLhost");
public static String port = SQL.getInstance().getConfig().getString("Config.SQLport");
public static String database = SQL.getInstance().getConfig().getString("Config.SQLdatabase");
public static String username = SQL.getInstance().getConfig().getString("Config.SQLusername");
public static String password = SQL.getInstance().getConfig().getString("Config.SQLpassword");
public static Connection con;

public static void connect(){

    if(!isConnected()){
        try {

            con = DriverManager.getConnection("jdbc:mysql://" + host + ":" + port + "/" + database, username, password);
            System.out.println("[SQL] Connected with MySQL.");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

public static boolean isConnected(){
    return (con == null ? false : true);
}

And here's the error report:

java.sql.SQLException: Access denied for user 'localhost'@'localhost' (using password: YES)

[21:04:26 WARN]: at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959)
[21:04:26 WARN]: at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3870)
[21:04:26 WARN]: at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3806)
[21:04:26 WARN]: at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:871)
[21:04:26 WARN]: at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1686)
[21:04:26 WARN]: at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1207)
[21:04:26 WARN]: at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2254)
[21:04:26 WARN]: at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2285)
[21:04:26 WARN]: at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2084)
[21:04:26 WARN]: at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:795)

[21:04:26 WARN]: at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:44)
[21:04:26 WARN]: at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
[21:04:26 WARN]: at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
[21:04:26 WARN]: at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
[21:04:26 WARN]: at java.lang.reflect.Constructor.newInstance(Unknown Source)
[21:04:26 WARN]: at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
[21:04:26 WARN]: at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)
[21:04:26 WARN]: at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327)
[21:04:26 WARN]: at java.sql.DriverManager.getConnection(Unknown Source)
[21:04:26 WARN]: at java.sql.DriverManager.getConnection(Unknown Source)

I hope you can help me. Greetings, Curbe.