Error while using DriverManager to connect to MySQL DB.

[Robinson Francis]

Dear ALL,

I have encountered some problems while trying to write a simple programme to connect with a MySQL db.

Below is the main() method code which calls the class to connect to the db.

package org.koushik.javabrains;

import org.koushik.javabrains.dao.jdbcDaoImpl;
import org.koushik.javabrains.model.Circle;

public class jdbcDemo {

	/**
	 * @param args
	 * 1)Initialize a DAO
	 * 2)Call a method of the DAO which will fetch the data.
	 * So write a DAO first before proceeding further in this class file.
	 * http://www.youtube.com/watch?v=B3gEbC37DAM&feature=relmfu  /
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		//initialize the DAO.
		Circle circle = null;
		circle = new jdbcDaoImpl().getCircle(1);
		System.out.println(circle.getName());
	}

}

The error seems to have happened in this DAO IMPLementation code.

package org.koushik.javabrains.dao;

import org.koushik.javabrains.model.Circle;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Date;
//import the logger files, to enable logging.
import java.util.logging.FileHandler;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.logging.SimpleFormatter;

/**
 * @param args
 * Responsible to talk to the DB & getting the value
 * One method to fetch the circle object form Db after passing the Circle id.
 * 
 */
public class jdbcDaoImpl {
	
	public Circle getCircle(int circleId){
		System.out.println("Getting connection.");
		//JDBC code to go here>
		// This will load the MySQL driver, each DB has its own driver
		// Load driver's class, initialize, register with DriverManager
		//Create a connection object.
		Circle circle = null;
		Connection conn = null;
		try{
			try {
				Class.forName("com.mysql.jdbc.Driver").newInstance();
			} catch (InstantiationException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (ClassNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			System.out.print("Initialize the client driver\n");
			//Initialize the client driver, need to know the specific String that denotes a driver.
			//jdbc:mysql://host_name:port/database name 
			//Get connection.
			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","ROOT", "root");
			if(!conn.isClosed())
				System.out.println("Successfully connected to " +
								   "MySQL server using TCP/IP...");
			PreparedStatement ps = conn.prepareStatement("SELECT * FROM circle WHERE id  = ?");
			ps.setInt(circleId, 1);
		
			//Execute the PreparedStatement
			//Initialize a Circle object to hold the record set returned by execution of the PreparedStatement.
			
			ResultSet rs = ps.executeQuery();
			if(rs.next()){
				circle  = new Circle(circleId, rs.getString("name"));
			}
			rs.close();
			ps.close();
			//return circle;
		
		}
		catch(SQLException x){
			x.printStackTrace();
		}
		finally{
			try {
				conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
		}
		
		return circle;	
	}//end of getCircle(int circleId)
	
}

The console output and the stack trace are as below:

Getting connection.
Initialize the client driver
java.sql.SQLException: Access denied for user 'ROOT'@'localhost' (using password: YES)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3597)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3529)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:935)
	at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4101)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1300)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2337)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2370)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2154)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
	at java.sql.DriverManager.getConnection(DriverManager.java:582)
	at java.sql.DriverManager.getConnection(DriverManager.java:185)
	at org.koushik.javabrains.dao.jdbcDaoImpl.getCircle(jdbcDaoImpl.java:50)
	at org.koushik.javabrains.jdbcDemo.main(jdbcDemo.java:19)
Exception in thread "Main Thread" java.lang.NullPointerException
	at org.koushik.javabrains.dao.jdbcDaoImpl.getCircle(jdbcDaoImpl.java:74)
	at org.koushik.javabrains.jdbcDemo.main(jdbcDemo.java:19)

Please help me on this guys. If there is any more info that I must include please let me know. Thank you all for your effort.

Very truly yours,
ROBINSON

[James Boswell]

The exception indicates you have provided an incorrect username and password when connecting. Should you not be using 'root' instead of 'ROOT' as the username?

[Rob Spoor]

And please KeepItDown, also in subject lines.

[Robinson Francis]

Thank you, all for your answer. I have managed to solve it.