Connect to the Oracle database - does not connect

I am new to JAVA and for the first time that I am trying to connect to an Oracle using JAVA data. Well, I get an error when you try to connect to the database. I can see that the error doesn't that make strings passed to make the databases of connection are NULL. Thus, an error (see error below).

Question
How is the 'connection' varriable is NULL?
It seems that the hold 'try' session was not executed. This session is broken?

ERROR

The database connection is not found: null
Database connection before call: null
Exception in thread "main" java.lang.NullPointerException
at TestOCIApp.main (TestOCIApp.java:39)


= JAVA START program =.

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

public class TestOCIApp {}

Public Shared Sub main (string args []) throws ClassNotFoundException,
SQLException {}

Fitting out = null;
try {}
Load the JDBC driver
String driverName = "oracle.jdbc.driver.OracleDriver";
Class.forName (driverName);

Create a connection to the CCM PROD database
String serverName = "192.168.2.144";
String portNumber = "1521;
String sid = "op01ccdb01";
String url = "JDBC: 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) {}
The database driver is not found
System.out.println ("could not find the connection to database:" + connection);
} catch (SQLException e) {}
Could not connect to the database
System.out.println ("could not connect to the database connection:" + connection);
}

System.out.println ("connection to the base before the call:" + connection);
Statement stmt = connection.createStatement ();
ResultSet rset = stmt.executeQuery ("select" driver Tester Hello OIC ' |) THE USER: '! ("' result from double ');
While (rset.next ())
System.out.println (RSet.GetString (1));
RSet.Close ();
stmt. Close();
Connection.Close;
}
}


= END of JAVA program =.

The try section runs very well but only partially because you get the exception "ClassNotFoundException", which means that it is impossible to load the Oracle driver class (so it does not reach the line where it says):

Class.forName(driverName);

You intercept this exception and then simply print a line "could not find the database connection: null". Then you let the code continue, obviously without you still initialize your variables.

I would recommend rewriting those catch blocks throw new RuntimeException so that the code will not continue any further when an error is detected in the try or don't catch not all of them if you donot want to manage them appropriately.

As for your problem, you probably have not added the ojdbc14.jar is to your project, and this is why it cannot find the class OracleDriver.

Finally, try adding {noformat}

{noformat} around your code when you post code.  It makes it a lot more readable.

Tags: Java

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