Connect Java with mysql in IntelliJ idea

I'm trying to connect java with mysql and I get these exceptions. These are my classes:

package com.javasdp.sdp;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.*;

public class Database {

    private Connection con;

    public void StartBd() throws Exception {

        if(con != null) return;

        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e){
            throw new Exception("No database");
        }

        String connectionURL = "jdbc:mysql://localhost:3306/SDP_INGESOFT?autoReconnect=true&useSSL=false";

        con = DriverManager.getConnection(connectionURL, "victor98", "solfito4702");
    }

    public void close(){
        if(con != null){
            try{
                con.close();
            } catch (SQLException e){
                e.printStackTrace();
            }
        }
    }
}


package com.javasdp.sdp;
public class MainClass {
    public static void main(String[] args) throws Exception {

        Database myConnectionDB = new Database();
        try {
            myConnectionDB.StartBd();
        } catch(Exception e){
            e.printStackTrace();
        }
        myConnectionDB.close();


        System.out.println("Hello, World!");
    }
}

And this is the error the program sends me:

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.Util.getInstance(Util.java:408)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:918)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2163)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2088)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:806)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at com.javasdp.sdp.Database.StartBd(Database.java:23)
    at com.javasdp.sdp.MainClass.main(MainClass.java:10)
Caused by: java.lang.NullPointerException
    at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:2997)
    at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1934)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1863)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1226)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2253)
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2104)
    ... 14 more