JDBC classnotfound exception

Question

I recently started JDBC. I installed JDBC drivers from ubuntu software center and run my first java program using JDBC.

import java.sql.*    
public class db
{
    static final String JDBC_DRIVER="com.mysql.jdbc.Driver";
    static final String DB_URL="jdbc:mysql://localhost/emp";
    static final String USER= "username";
    static final String PASS="password";
    public static void main(String [] args)
    {
        Connection conn=DriverManager.getConnection(JDBC_DRIVER);
        Statement stmt=null;
        try
        {
            Class.forName("com.mysql.jdbc.Driver");
            System.out.println("Connecting to database");
            System.out.println("Creting statement");
            String sql;
            stmt=conn.createStatement();
            sql="select id, first last, age from Employee";
            ResultSet rs= stmt.executeQuery(sql);
            while(rs.next())
            {
                int id=rs.getInt("id");
                int age=rs.getInt("age");
                String first=rs.getString("first");
                String last=rs.getString("Last");
                System.out.print("ID: "+id);
                System.out.print(", Age: " +age);
                System.out.print(", First: "+first);
                System.out.println(", Last: "+last);
            }
            rs.close();
            stmt.close();
            conn.close();
        }
        catch(SQLException se)
        {
            se.printStackTrace();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        finally
        {
            try
            {
                if(stmt!=null)
                    conn.close();
            }
            catch(SQLException se)
            {
                se.printStackTrace();
            }
        }
    }
}

I created "emp" database and I am trying to browse its content using JDBC. when i use

javac db.java

everything works ok. However when I run it via

java db

it gives me java.lang.classnotfoundException. I included CLASSPATH=CLASSPATH://user/share/java/mysql-connector-java.jar into bashrc file. Can anybody help me to solve this problem?

If you are using any IDE add the jar file in the `WEB-INF/lib`, if it is a web-app, add it to `lib` folder and try it. — Subramanyam M, Dec 02 '15 at 13:19
I strongly encourage you to use a build and dependency management tool like Maven, Ant + Ivy, Gradle, etc. instead of manually compile and set the classpath. — Eric Citaire, Dec 02 '15 at 15:03

score 0 · Answer 1 · edited May 23 '17 at 12:23

0

Put Class.forName("com.mysql.jdbc.Driver"); before DriverManager.getConnection() call, not after it
- Note that it is also possible you won't need this anymore - see Class.forName(JDBC_DRIVER) no longer needed?
DriverManager.getConnection() needs URL as a parameter, not driver class name, so use Connection conn=DriverManager.getConnection(DB_URL);

edited May 23 '17 at 12:23

Community

1
1

answered Dec 02 '15 at 13:21

Jiri Tousek

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It is quite likely that they don't need the `Class.forName` statement at all. – Gord Thompson Dec 02 '15 at 13:32
what URL do you mean? sorry I am a newbie in both java and JDBC – olzha bala Dec 02 '15 at 13:40
For each type of database, you ought to give a proper URL. In the case of MySql, it would be something like : jdbc:mysql://:/ , that's what you have in your DB_URL . – Arnaud Dec 02 '15 at 13:43
@olzhabala You have a mysql db URL in your `DB_URL` constant, so that's what I used in my answer. – Jiri Tousek Dec 02 '15 at 13:44
I added conn=DriverManager.getConnection(DB_URL); statement after class.forName() but still have the same error – olzha bala Dec 02 '15 at 14:07
@GordThompson ok, thanks for pointing that out. Edited the post accordingly, and cleaned up my comments on this. – Jiri Tousek Dec 02 '15 at 14:58

JDBC classnotfound exception

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