java lang classnotfoundexception com mysql jdbc driver

Question

I am facing an error with my code while debugging it. I am trying to write the code for connecting a singleton class with the database mysql. I am new to Java and need some assistance on what the error is. Under this line is the code which I used:-

package com.glomindz.mercuri.util; 
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException; 


public class MySingleTon { 
String url = "jdbc:mysql://localhost:3306/"; 
String dbName = "test"; 
String driver = "com.mysql.jdbc.Driver"; 
String userName = "root"; 
String password = ""; 

private static MySingleTon myObj;
private Connection Con ;
private MySingleTon() { 

    System.out.println("Hello"); 
    Con= createConnection(); 

} 

@SuppressWarnings("rawtypes") 
public Connection createConnection() { 
          Connection connection = null; 
          try { 

// Load the JDBC driver 
Class driver_class = Class.forName(driver); 
Driver driver = (Driver) driver_class.newInstance(); 
DriverManager.registerDriver(driver); 
connection = DriverManager.getConnection(url + dbName);
} catch (ClassNotFoundException e) { e.printStackTrace(); 
} catch (SQLException e) { e.printStackTrace(); 
} catch (IllegalAccessException e) { e.printStackTrace();
} catch (InstantiationException e) { e.printStackTrace(); 
} 
return connection; 
} 
/** 
* Create a static method to get instance. 
*/ public static MySingleTon getInstance() { 
          if (myObj == null) { 
              myObj = new MySingleTon(); 
}
return myObj;
}
public static void main(String a[]) {

      MySingleTon st = MySingleTon.getInstance(); 
  } 
}

Answer 1

I assume that your mysql connectivity library is not included in the project you are in. In order to rectify the error you are facing, try to use either the Maven Projects Solution or the All Projects Solution. In the former, add the mysql-connector dependency to the given project file pom.xml which is displayed below:-

<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.39</version> </dependency>

The latter, add the jar library to the given project manually and follow the steps:-

Right Click the project -- > build path -- > configure build path

In the Libraries Tab press Add External Jar and Select your jar. As the file from the MYSQL connectivity library is not found, Java will give an exception while you build your project. In other words, to conclude is that once you add the library to the project, then Java will be able to locate the driver com.mysql.jdbc.Driver.

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