java - Cannot call Method in JDBC file from Servlet file -

public class jdbc_pro extends helloworld {   //database essential  public string jdbc_driver = "com.mysql.jdbc.driver"; public string db_url = "jdbc:mysql://localhost:3306/kalinga"; public string user = "root"; public string pass = "welcome123"; public  connection con = null ;    public jdbc_pro(){       jdbc_driver = "com.mysql.jdbc.driver";      db_url = "jdbc:mysql://localhost:3306/kalinga";      user = "root";      pass = "welcome123";         try{       class.forname(jdbc_driver);         //system.out.println("connecting database");         con = drivermanager.getconnection(db_url, user, pass);         }       catch(exception e){system.out.println(e);         }    } public void insertdata(string state,string city,string age,string dep,string person,string amount,string des){       try{          string sql ="insert kan values(?,?,?,?,?,?,?)";         preparedstatement pst = con.preparestatement(sql);         pst.setstring(1,state);         pst.setstring(2, city);         pst.setstring(3, age);         pst.setstring(4, dep);         pst.setstring(5, person);         pst.setstring(6, amount);         pst.setstring(7, des);          int numrowschanged = pst.executeupdate();         system.out.println(numrowschanged);          pst.close();         con.close();     }catch(exception e){ e.printstacktrace();}  } 

abov jdbc file ... want call method insertdata() servlet file . when run jdbc file alone the data getting updated table when call method servlet file like

jdbc_pro b = new jdbc_pro(); b.insertdata("the arguments goes here.."); 

exception

java.lang.classnotfoundexception: com.mysql.jdbc.driverjava.lang.nullpointerexception 

both files in same package! can please solve problem

have added mysql connector jar in project?

i guess missing mysql connector jar throwing exception

java.lang.classnotfoundexception: com.mysql.jdbc.driverjava.lang.nullpointerexception