Database MySQL con JAVA

package myDatabase;

import java.sql.*;


public class DBConnect {
	private Connection conn;
	private Statement st;
	private ResultSet rs;
	
	public DBConnect() {
		try {
			Class.forName("com.mysql.jdbc.Driver");
			
			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "test", "test");
			st =conn.createStatement();
			
			
			
		} catch(Exception ex) {
			System.out.println("Error:" +ex);
		}
	}

	public void getData() {
		try {
			
			String query =	"select * from persona";
			rs = st.executeQuery(query);
			System.out.println("Records form database");
			while (rs.next()) {
				String name =rs.getString("name");
				String age = rs.getString("age");
				System.out.println("Name: "+name+"  Age: "+age);
			}
			
		}catch(Exception ex) {
			System.out.println("Error"+ex);
		}
	}
}

package myDatabase;



public class MainApplication {

	public static void main(String[] args) {
		
		DBConnect connect = new DBConnect();
		connect.getData();
		}
	
	}

Error:com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: 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.
Errorjava.lang.NullPointerException