Problems loading the driver

[enrique...@mac.com]

Hello:

I am trying to compile a very simple Java J2SE program that will connect to a Postgres database. I am using:

* an Apple computer running Mac OS/X 10.4

* Postgres 8.0

* JDBC driver postgresql-8.0-311.jdbc3.jar

The JDBC jar file IS in the CLASSPATH environment variable. The code of the program is the following:

    public static void main (String[] args) {

        

        try {

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

        } catch (ClassNotFoundException e) {

            System.out.println (e.getMessage ());

            e.printStackTrace ();

        }

The program compiles fine but the error message I get when I run the program is the following:

[Session started at 2005-06-24 23:32:14 -0500.]

org.postgresql.Driver

java.lang.ClassNotFoundException: org.postgresql.Driver

    at java.net.URLClassLoader$1.run(URLClassLoader.java:199)

    at java.security.AccessController.doPrivileged(Native Method)

    at java.net.URLClassLoader.findClass(URLClassLoader.java:187)

    at java.lang.ClassLoader.loadClass(ClassLoader.java:289)

    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274)

    at java.lang.ClassLoader.loadClass(ClassLoader.java:235)

    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)

    at java.lang.Class.forName0(Native Method)

    at java.lang.Class.forName(Class.java:141)

    at gastos.main(gastos.java:17)

I have tried placing the JDBC jar file at different directories while adjusting the CLASSPATH variable but I keep getting the same annoying error. I also tried the -cp flag when invoking 'java' to execute the program, but it does not work. I ran out of ideas and the exercise is becoming very frustrating. Any suggestions will be highly appreciated. Thanks a lot in advance.

Regards,

Enrique

[Oliver Jowett]

enrique...@mac.com wrote:

> The JDBC jar file IS in the CLASSPATH environment variable. The code of
> the program is the following:

> org.postgresql.Driver
> java.lang.ClassNotFoundException: org.postgresql.Driver

This means that the driver jar *isn't* in your classpath.

What is the exact value of your CLASSPATH, have you exported the
CLASSPATH environment variable, where have you placed the driver jar,
and what is the Java command line you are trying?

-O

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[Enrique Ibarra]

Oliver, thank you very much for your quick response. It seems that I
will have to check this problem with Apple support. The jar driver is
in fact in the CLASSPATH variable but somehow its value is not being
correctly read by java. I was originally working with Xcode (Apple's
IDE). I tried specifying both the CLASSPATH environment variable and
java's -cp switch in the IDE but it did not work. Then I switched to
old-fashioned emacs and a command terminal and I was able to make the
program run, but only when I specify the -cp option in the java
command line. If I do not specify the -cp switch then the program
does not run (even though the jar driver is in the CLASSPATH). I have
not been able to make this program run from the Xcode IDE. Here is
the output of the command terminal to illustrate this problem. Thanks
again.

{~/Ixe/Proyectos/tarme}% javac actgastos.java
{~/Ixe/Proyectos/tarme}% echo $CLASSPATH
/usr/local/lib/postgresql.jar:.:
{~/Ixe/Proyectos/tarme}% java actgastos gastos.csv

org.postgresql.Driver
java.lang.ClassNotFoundException: org.postgresql.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:199)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:
274)
at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:
302)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:141)

at actgastos.main(actgastos.java:8)
No suitable driver
java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getConnection(DriverManager.java:532)
at java.sql.DriverManager.getConnection(DriverManager.java:171)
at actgastos.main(actgastos.java:15)
{~/Ixe/Proyectos/tarme}% java -cp /usr/local/lib/postgresql.jar:.:
actgastos gastos.csv
{~/Ixe/Proyectos/tarme}%

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