Connecting to Oracle Database - Not Connecting

Question

I am new to JAVA and for the first time I am trying to connect to an Oracle data using JAVA. Well, I am getting an error when trying to connect to the database. What I can see the error has to do that the strings passed to make the databases connection are NULL. So, an error (see error below).
Question
How come the "connection" varriable is NULL?
It appears that the hold "try" session is not executed. Is this session out of order?
ERROR
Could not find the database connection: null
Database connection before call: null
Exception in thread "main" java.lang.NullPointerException
     at TestOCIApp.main(TestOCIApp.java:39)
========= JAVA Program START =======
//import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestOCIApp {
public static void main(String args[]) throws ClassNotFoundException,
SQLException {
     Connection connection = null;
     try {
     // Load the JDBC driver
     String driverName = "oracle.jdbc.driver.OracleDriver";
     Class.forName(driverName);
     // Create a connection to the CCMS PROD database
     String serverName = "192.168.2.144";
     String portNumber = "1521";
     String sid = "op01ccdb01";
     String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;
     String username = "user-id";
     String password = "password";
     connection = DriverManager.getConnection(url, username, password);
     System.out.println("connection value: " + connection);
     } catch (ClassNotFoundException e) {
     // Could not find the database driver
          System.out.println("Could not find the database connection: " + connection);
     } catch (SQLException e) {
     // Could not connect to the database
          System.out.println("Could not connect to the database connection: " + connection);
     System.out.println("Database connection before call: " + connection);
     Statement stmt = connection.createStatement();
ResultSet rset = stmt.executeQuery("select 'Hello OCI driver tester '||USER||'!' result from dual");
while (rset.next())
System.out.println(rset.getString(1));
rset.close();
stmt.close();
connection.close();
========= JAVA Program END =========

Answer 1

The try section is being executed just fine but only partially because you get the exception "ClassNotFoundException", which means it cannot load the Oracle driver class (so it fails at the line where it says):
Class.forName(driverName);You catch this exception, and then just print a line "Could not find the database connection: null". Then you let the code continue, obviously without having initialized your variables yet.
I would recommend rewriting those catch blocks to throw a new RuntimeException so the code will not continue further when an error is detected in the try, or to not catch them not all if you donot want to handle them there in a proper fashion.
As to your problem, you probably have not added the ojdbc14.jar to your project, and that's why it cannot find the OracleDriver class.
Finally, try to add {noformat}{noformat} around your code when you post code.  It makes it a lot more readable.