JDBC Code error

[mert ozkaya]

Hi All,

I am very new to JDBC programming.
I am using Mac OS X and trying get the following code run. I have already installed mysql into my machine. However, when I compiled and run the code, I got the error that I have given below the code. Can you please help me on finding out the reason for this error?

Code is :

//STEP 1. Import required packages
import java.sql.*;

public class Database_coding {
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
   static final String DB_URL = "jdbc:mysql://127.0.0.1:3306/mpp/";

   
   //  Database credentials
   static final String USER = "root";
   static final String PASS = "";
   
   public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
   try{
      //STEP 2: Register JDBC driver
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: Open a connection
      System.out.println("Connecting to database...");
      conn = DriverManager.getConnection(DB_URL, USER, PASS);

      //STEP 4: Execute a query
      System.out.println("Creating database...");
      stmt = conn.createStatement();
      
      String sql = "CREATE DATABASE STUDENTS";
      stmt.executeUpdate(sql);
      System.out.println("Database created successfully...");
   }catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }finally{
      //finally block used to close resources
      try{
         if(stmt!=null)
            stmt.close();
      }catch(SQLException se2){
      }// nothing we can do
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try
   System.out.println("Goodbye!");
}//end main
}//end JDBCExample

Connecting to database...
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.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:400)
	at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1038)
	at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:339)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2247)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2280)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2079)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:400)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
	at java.sql.DriverManager.getConnection(DriverManager.java:571)
	at java.sql.DriverManager.getConnection(DriverManager.java:215)
	at Database_coding.main(Database_coding.java:23)
Caused by: java.net.ConnectException: Connection refused
	at java.net.PlainSocketImpl.socketConnect(Native Method)
	at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
	at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
	at java.net.Socket.connect(Socket.java:579)
	at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:214)
	at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:298)
	... 15 more
Goodbye!

[Tapas Chand]

Are you sure the database is started?
Looks like database port is not listening.
What is output of

netstat -an | grep 3306

[Tim Cooke]

Also please BeForthrightWhenCrossPostingToOtherSites. We don't mind if you cross post to other sites, but we do ask that you tell us you've done so.

http://www.javaprogrammingforums.com/jdbc-databases/45128-jdbc-code-error.html

[mert ozkaya]

Hi,

Sorry for the cross posting - will delete the other.

I think that I have resolved the problem. The default port is 3307- not 3306. When I have made the regarding change, it seems that I got the code working.

Thanks.

[Tapas Chand]

Good job.
But what about the blank string in password?
I thought we need to pass null instead of blank string for an user having no password.

[K. Tsang]

mert ozkaya wrote:

I think that I have resolved the problem. The default port is 3307- not 3306. When I have made the regarding change, it seems that I got the code working.

Thanks.

MySQL default port is 3306. Unless you have changed it to 3307, the port should have been 3306.