Java-JDBC-MySQL Error

Question

I'm trying to get my java program to talk to a MySQL DB.

So i did some reading and downloaded MySQL Connector/J. I've extracted it into my home directory ~. Here are the contents.

user@hamster:~$ ls
LoadDriver.class LoadDriver.java mysql-connector-java-5.1.18-bin.jar

The contents of LoadDriver.java are

user@hamster:~$ cat LoadDriver.java 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
// Notice, do not import com.mysql.jdbc.*
// or you will have problems!
public class LoadDriver {
 public static void main(String[] args) {
 try {
 // The newInstance() call is a work around for some
 // broken Java implementations
 Class.forName("com.mysql.jdbc.Driver").newInstance();
 } catch (Exception ex) {
 System.out.println(ex);
 }
 }
}

The contents are the same from http://dev.mysql.com/doc/refman/5.1/en/connector-j-usagenotes-basic.html#connector-j-usagenotes-connect-drivermanager with the only change that the Exception is being printed to console in the catch block.

I compile it as follows

leonard@hamster:~$ javac LoadDriver.java

When I try to execute it, the following is the ouput.

leonard@hamster:~$ java LoadDriver
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

This output is consistent with the executing command, but when trying to run it with the prescribed CLASSPATH method I run into the following issue.

leonard@hamster:~$ java -cp /home/leonard/mysql-connector-java-5.1.18-bin.jar LoadDriver
Exception in thread "main" java.lang.NoClassDefFoundError: LoadDriver
Caused by: java.lang.ClassNotFoundException: LoadDriver
 at java.net.URLClassLoader1ドル.run(URLClassLoader.java:217)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: LoadDriver. Program will exit.

Am I missing something? How do I get MySQL's own code samples running.

• LeonardPeris: I did try by setting the $CLASSPATH environment variable but it gives me the same error
• LeonardPeris: @brunopereira81 I felt this was one time Ubuntu specific quirk...
• brunopereira81: java -cp . LoadDriver returns the same fault?
• LeonardPeris: It returns java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

Answer 1

You need to have both the jar, and the current directory, on the classpath.

java -cp .:/home/leonard/mysql-connector-java-5.1.18-bin.jar LoadDriver