Обсуждение: java.sql.SQLException: No suitable driver

Hi Everybody, when I try to run my program, I get the following error message:

java.sql.SQLException: No suitable driver

        at java.sql.DriverManager.getConnection(Unknown Source)

        at java.sql.DriverManager.getConnection(Unknown Source)

        at Database.<init>(Database.java:20)

        at Gateway.main(Gateway.java:19)

Exception in thread "main" java.lang.NullPointerException

        at Database.SQLget(Database.java:71)

        at Gateway.main(Gateway.java:33)

My connect code is:

try {

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

      }catch (ClassNotFoundException e){

      }

      try {

        db = DriverManager.getConnection("jdbc:postgresql://hostname/" + dbName,"bruger","kode");

      } catch (SQLException e) {

        e.printStackTrace();

      }

On my system I have putted the jdbc driver for postgres into the classpath:

hostname:~$ echo $CLASSPATH

/usr/share/java/pg74.216.jdbc3.jar

Java version:

hostname:~$ java -version

java version "1.5.0_06"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)

Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)

As far as I know it should work since, it is correct in the classpath. I have also tried with other postgres jdbc drivers. In my IDE(Eclipse), it works fine, but on my production server it gives the error. 

I've also tried to run the program with the -classpath flag, with the same result.

Have I simply forgotten something, or is there something seriously wrong?

Thanks in advance.

5 will get you 10 that your class path isn't setup correctly. Try adding ex.printStackTrace() to the catch handler for Class.forName

Well, it gives me:

java.lang.ClassNotFoundException: org.postgresql.Driver
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        at Database.<init>(Database.java:16)
        at Gateway.main(Gateway.java:19)

But I think you're right... But my problem is, that if I try to run it with the classpath flag, and also the classpath environment vartiable, it fails.
The path is correct.

I believe that I have overseen something, but I have looked over the setup a dusin of times now, and I can't spot it.


Dave Cramer wrote:

5 will get you 10 that your class path isn't setup correctly. Try adding ex.printStackTrace() to the catch handler for Class.forName

Dave

On 27-Apr-06, at 8:19 AM, Mads N. Vestergaard wrote:

Hi Everybody, when I try to run my program, I get the following error message:

java.sql.SQLException: No suitable driver

        at java.sql.DriverManager.getConnection(Unknown Source)

        at java.sql.DriverManager.getConnection(Unknown Source)

        at Database.(Database.java:20)

        at Gateway.main(Gateway.java:19)

Exception in thread "main" java.lang.NullPointerException

        at Database.SQLget(Database.java:71)

        at Gateway.main(Gateway.java:33)

My connect code is:

try {

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

      }catch (ClassNotFoundException e){

      }

      try {

        db = DriverManager.getConnection("jdbc:postgresql://hostname/" + dbName,"bruger","kode");

      } catch (SQLException e) {

        e.printStackTrace();

      }

On my system I have putted the jdbc driver for postgres into the classpath:

hostname:~$ echo $CLASSPATH

/usr/share/java/pg74.216.jdbc3.jar

Java version:

hostname:~$ java -version

java version "1.5.0_06"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)

Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)

As far as I know it should work since, it is correct in the classpath. I have also tried with other postgres jdbc drivers. In my IDE(Eclipse), it works fine, but on my production server it gives the error. 

I've also tried to run the program with the -classpath flag, with the same result.

Have I simply forgotten something, or is there something seriously wrong?

Thanks in advance.

Mads,

Hi Dave,

My Classpath is:

hostname:~$ echo $CLASSPATH

/usr/share/java/pg74.216.jdbc3.jar

And the file exists:
hostname:~$ ls -la /usr/share/java/pg74.216.jdbc3.jar 
-rwxr-xr-x  1 root root 210371 2006-04-27 09:52 /usr/share/java/pg74.216.jdbc3.jar

Dave Cramer wrote:

Mads,

What is your classpath.

inevitably this is the problem.

Dave

On 27-Apr-06, at 9:31 AM, Mads N. Vestergaard wrote:

Well, it gives me:

java.lang.ClassNotFoundException: org.postgresql.Driver
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        at Database.<init>(Database.java:16)
        at Gateway.main(Gateway.java:19)

But I think you're right... But my problem is, that if I try to run it with the classpath flag, and also the classpath environment vartiable, it fails.
The path is correct.

I believe that I have overseen something, but I have looked over the setup a dusin of times now, and I can't spot it.


Dave Cramer wrote:

5 will get you 10 that your class path isn't setup correctly. Try adding ex.printStackTrace() to the catch handler for Class.forName

Dave

On 27-Apr-06, at 8:19 AM, Mads N. Vestergaard wrote:

Hi Everybody, when I try to run my program, I get the following error message:

java.sql.SQLException: No suitable driver

        at java.sql.DriverManager.getConnection(Unknown Source)

        at java.sql.DriverManager.getConnection(Unknown Source)

        at Database.(Database.java:20)

        at Gateway.main(Gateway.java:19)

Exception in thread "main" java.lang.NullPointerException

        at Database.SQLget(Database.java:71)

        at Gateway.main(Gateway.java:33)

My connect code is:

try {

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

      }catch (ClassNotFoundException e){

      }

      try {

        db = DriverManager.getConnection("jdbc:postgresql://hostname/" + dbName,"bruger","kode");

      } catch (SQLException e) {

        e.printStackTrace();

      }

On my system I have putted the jdbc driver for postgres into the classpath:

hostname:~$ echo $CLASSPATH

/usr/share/java/pg74.216.jdbc3.jar

Java version:

hostname:~$ java -version

java version "1.5.0_06"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)

Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)

As far as I know it should work since, it is correct in the classpath. I have also tried with other postgres jdbc drivers. In my IDE(Eclipse), it works fine, but on my production server it gives the error. 

I've also tried to run the program with the -classpath flag, with the same result.

Have I simply forgotten something, or is there something seriously wrong?

Thanks in advance.

Mads,

Hi,

Well it gives me a lot of debug information. http://timmy.dk/debug.txt .

I ran:

hostname:~$ java -verbose -cp /usr/share/java/pg74.216.jdbc3.jar -jar program.jar

Dave Cramer wrote:

Mads,

And how do you execute the program ? One thing that can help is to run java -verbose to see what it is doing.

Dave

On 27-Apr-06, at 9:46 AM, Mads N. Vestergaard wrote:

Hi Dave,

My Classpath is:

hostname:~$ echo $CLASSPATH

/usr/share/java/pg74.216.jdbc3.jar

And the file exists:
hostname:~$ ls -la /usr/share/java/pg74.216.jdbc3.jar 
-rwxr-xr-x  1 root root 210371 2006-04-27 09:52 /usr/share/java/pg74.216.jdbc3.jar
 

Dave Cramer wrote:

Mads,

What is your classpath.

inevitably this is the problem.

Dave

On 27-Apr-06, at 9:31 AM, Mads N. Vestergaard wrote:

Well, it gives me:

java.lang.ClassNotFoundException: org.postgresql.Driver
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        at Database.<init>(Database.java:16)
        at Gateway.main(Gateway.java:19)

But I think you're right... But my problem is, that if I try to run it with the classpath flag, and also the classpath environment vartiable, it fails.
The path is correct.

I believe that I have overseen something, but I have looked over the setup a dusin of times now, and I can't spot it.


Dave Cramer wrote:

5 will get you 10 that your class path isn't setup correctly. Try adding ex.printStackTrace() to the catch handler for Class.forName

Dave

On 27-Apr-06, at 8:19 AM, Mads N. Vestergaard wrote:

Hi Everybody, when I try to run my program, I get the following error message:

java.sql.SQLException: No suitable driver

        at java.sql.DriverManager.getConnection(Unknown Source)

        at java.sql.DriverManager.getConnection(Unknown Source)

        at Database.(Database.java:20)

        at Gateway.main(Gateway.java:19)

Exception in thread "main" java.lang.NullPointerException

        at Database.SQLget(Database.java:71)

        at Gateway.main(Gateway.java:33)

My connect code is:

try {

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

      }catch (ClassNotFoundException e){

      }

      try {

        db = DriverManager.getConnection("jdbc:postgresql://hostname/" + dbName,"bruger","kode");

      } catch (SQLException e) {

        e.printStackTrace();

      }

On my system I have putted the jdbc driver for postgres into the classpath:

hostname:~$ echo $CLASSPATH

/usr/share/java/pg74.216.jdbc3.jar

Java version:

hostname:~$ java -version

java version "1.5.0_06"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)

Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)

As far as I know it should work since, it is correct in the classpath. I have also tried with other postgres jdbc drivers. In my IDE(Eclipse), it works fine, but on my production server it gives the error. 

I've also tried to run the program with the -classpath flag, with the same result.

Have I simply forgotten something, or is there something seriously wrong?

Thanks in advance.

Mads N. Vestergaard wrote:

> hostname:~$ java -verbose -cp /usr/share/java/pg74.216.jdbc3.jar -jar
> program.jar
>

-jar causes the JVM to completely ignore any additional classpath you
specify.

Instead, try:

java -cp /usr/share/java/pg74.216.jdbc3.jar:program.jar ProgramMainClass

-O

Hi Aliver,

there isn't any conditional files in the environment variable CLASSPATH,
and the program runs fine, it just can't connect to the database.


Oliver Jowett wrote:
> Mads N. Vestergaard wrote:
>
>> hostname:~$ java -verbose -cp /usr/share/java/pg74.216.jdbc3.jar -jar
>> program.jar
>>
>
> -jar causes the JVM to completely ignore any additional classpath you
> specify.
>
> Instead, try:
>
> java -cp /usr/share/java/pg74.216.jdbc3.jar:program.jar ProgramMainClass
>
> -O

Mads N. Vestergaard wrote:
> Hi Aliver,
>
> there isn't any conditional files in the environment variable CLASSPATH,
> and the program runs fine, it just can't connect to the database.

I am talking about both the CLASSPATH environment variable and the -cp
command line argument. In my experience, if you specify -jar, both are
ignored and classes are only loaded from the standard locations, and the
single jarfile parameter given to -jar ("program.jar" in your case).

Have you tried the command line I suggested?

>> java -cp /usr/share/java/pg74.216.jdbc3.jar:program.jar ProgramMainClass

Please try this and let us know if it works.

I would also suggest that silently ignoring ClassNotFoundException, as
the code you originally posted does, is a Really Bad Idea. That code is
masking the real source of the error: namely, that the driver classes
are *not* in your classpath.

-O

Hi Oliver...

That seems to work just perfectly....


Oliver Jowett wrote:
> Mads N. Vestergaard wrote:
>> Hi Aliver,
>>
>> there isn't any conditional files in the environment variable CLASSPATH,
>> and the program runs fine, it just can't connect to the database.
>
> I am talking about both the CLASSPATH environment variable and the -cp 
> command line argument. In my experience, if you specify -jar, both are 
> ignored and classes are only loaded from the standard locations, and 
> the single jarfile parameter given to -jar ("program.jar" in your case).
>
> Have you tried the command line I suggested?
>
>>> java -cp /usr/share/java/pg74.216.jdbc3.jar:program.jar 
>>> ProgramMainClass
>
> Please try this and let us know if it works.
>
> I would also suggest that silently ignoring ClassNotFoundException, as 
> the code you originally posted does, is a Really Bad Idea. That code 
> is masking the real source of the error: namely, that the driver 
> classes are *not* in your classpath.
>
> -O
>
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