PreparedStatement throws java.lang.NullPointerException

Question

I keep getting a null pointer exception when trying to insert a record into a database. I'm in an into net apps class, so my this is my first time dealing with databases within eclipse. I believe this line initializes my connection variable:

this.connection = DriverManager.getConnection(url, uname, pwd);

...but it still says that connection is null. The line it refers to is:

PreparedStatement ps = connection.prepareStatement(query);

package dbHelpers;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import package1.Customer;


public class AddCustomerQuery {
public Connection connection;

public AddCustomerQuery(String dbName, String uname, String pwd){
    String url = "jdbc:mysql://localhost:3306/" + dbName;

    try {
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        this.connection = DriverManager.getConnection(url, uname, pwd); 
    } catch (InstantiationException | IllegalAccessException
            | ClassNotFoundException | SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public void addCustomer(Customer customer){

    String query = "insert into customer (firstName, lastName, emailAddress, password, gender, phoneNumber, street, city, state, zip) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
    try {   
    PreparedStatement ps = connection.prepareStatement(query);
        ps.setString(1, customer.getFirstName());
        ps.setString(2, customer.getLastName());
        ps.setString(3, customer.getEmailAddress());
        ps.setString(4, customer.getPassword());
        ps.setString(5, customer.getGender());
        ps.setString(6, customer.getPhoneNumber());
        ps.setString(7, customer.getStreet());
        ps.setString(8, customer.getCity());
        ps.setString(9, customer.getState());
        ps.setString(10, customer.getZip());

        ps.executeUpdate();

    } catch (SQLException e) {
        // TODO Auto-generated catch block
                e.printStackTrace();
    }

}

}

Do you call AddCustomerQuery() (bad name btw) before calling addCustomer() ? — Nir Alfasi
try Class.forName("com.mysql.jdbc.Driver"); i.e. remove newInstance() it worked for me that way :/ — KNU
@user3562811 you must use/instantiate the object of this class this way : AddCustomerQuery objReference = new AddCustomerQuery("CUSTOMER_TABLE", "root","root"); and then use it as objReference.addCustomer(customerObj) — KNU

Sairam Sairam · Accepted Answer · 2014-04-23T03:53:18

First check your mysql daatbase server username,password,database name etc..,. Because by default mysql server port number is 3306,may be while installation time you changed port number of your server.

PreparedStatement throws java.lang.NullPointerException

1 Answers