SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

public void connect()
{
        conn = null;
        try
        {
            conn =   DriverManager.getConnection("jdbc:mysql://localhost/test?" +
                                   "user=user&password=pass");
        }
        catch (SQLException ex)
        {
    // handle any errors
    System.out.println("SQLException: " + ex.getMessage());
    System.out.println("SQLState: " + ex.getSQLState());
    System.out.println("VendorError: " + ex.getErrorCode());
        }