How to resolve 'No suitable driver found' error

Question

I am running Netbeans 8.0.2. I was learning about JDBC and wanted to connect it to a PostgreSQL database. I looked up for all possible answers but no answer made it work.

I have also chosen the library on the left side menu as PostgreSQL JDBC Driver -postgresql-9.2-1002.jdbc4.jar

The error shown is:

SQL exception occuredjava.sql.SQLException: No suitable driver found for Jdbc:postgresql://localhost:5432/postgres

Here's the code:

try   { 

    Class.forName("org.postgresql.Driver");

  }
  catch(ClassNotFoundException e) {
     System.out.println("Class not found "+ e);
  }
     try {

     Connection con = DriverManager.getConnection
     ("Jdbc:postgresql://localhost:5432/postgres","postgres",
     "gautam");

     Statement stmt = con.createStatement();
     ResultSet rs = stmt.executeQuery
     ("SELECT * FROM role");
     System.out.println("id  name");

     while (rs.next()) {
        int id = rs.getInt("id");
        String name = rs.getString("name");
        System.out.println(id+"   "+name);

     }
  }
  catch(SQLException e){
     System.out.println("SQL exception occured" + e);
  }

Solution 1

I quickly tried your code and first got the same error:

With the correction to: DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres", "postgres","gautam"); it worked.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class NewClass {

    public void initialize() {
        try {
            Class.forName("org.postgresql.Driver");
        } catch (ClassNotFoundException e) {
            System.out.println("Class not found " + e);
        }
        try {
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres", "postgres","gautam");
            Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM role");
            System.out.println("id  name");

            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                System.out.println(id + "   " + name);

            }
        } catch (SQLException e) {
            System.out.println("SQL exception occured" + e);
        }
    }

    public static void main(String[] args) {
        new NewClass().initialize();
    }

}

---

The DriverManager asks every driver that is registered to it if it can read the url: "jdbc:postgresql://localhost:5432/postgres".
The first driver that returns true is used.
In your case no driver returned true.
The Method of the driver, that returns true or false is acceptsURL("jdbc:postgresql://localhost:5432/postgres")

You can test it with:

    try {
        Enumeration<Driver> drivers = DriverManager.getDrivers();
        while (drivers.hasMoreElements()) {
            Driver nextElement = drivers.nextElement();
            JOptionPane.showMessageDialog(null, nextElement.acceptsURL("jdbc:postgresql://localhost:5432/postgres"));
            JOptionPane.showMessageDialog(null, nextElement.acceptsURL("Jdbc:postgresql://localhost:5432/postgres"));
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }

Solution 2

I am using NetBeans 11.1 I 've got the same error message as in the title of this thread. I was able to compile and run my Java code on the Linux command line.

What I have overlooked since two days was the following error message in NetBeans, resp. I didn't connect this error message with my problem:

skip non existing resourceDirectory /home/thatsme/NetBeansProjects/myproject/src/main/resources

1. I created this directory manually on the command line
2. I copied the file with the postgresql driver "postgres-42.2.8.jar" into this directory

And since then my code runs also fine in NetBeans. I know, this is a very special error, but maybe it will help another one too. Just want to give something back here.

EDIT: I had the same problem with the ORACLE file ojdbc8.jar and my above mentioned solution didn't help. But after I unpacked ojdbc8.jar it worked fine.

$ jar xf ojdbc8.jar

If I run my application outside Netbeans/Maven then it works also fine with the packed version in the CLASSPATH.