MySQL and Java - getting program to work

Question

I am setting up mysql to run sql from a Java program on my pc at home and probably biting off more than I can chew. I get these messages when executing the java program ExecuteSQL.java:
Exception in thread "main" java.lang.NoClassDefFoundError: Test2 <wrong name: MyProjects/test2/Test2>
at java.lang.ClassLoader.defineClass0<Native Method>
at java.lang.ClassLoader.defineClass<Unknown Source>
at java.security.SecurityClassLoader.defineClass<Unknown Source>
at java.net.URLClassLoader.defineClass<Unknown Source>
at java.net.URLClassLoader.access$100<Unknown Source>
at java.net.URLClassLoader$1.run<Unknown Source>
at java.security.AccessController.ddPrivileged<Native Method>
at java.lang.ClassLoader.findClass<Unknown Source>
at java.lang.ClassLoader.loadClass<Unknown Source>
at sun.misc.Launcher$AppClassLoader.loadClass<Unknown Source>
at java.lang.ClassLoader.loadClass<Unknown Source>
at java.lang.ClassLoader.loadClassInternal<Unknown Source>
This is what I did.
I created a folder on my C: drive named MySQL.
I downloaded these two zip files form the MySQL website
     * mysql-connector-java-3.0.11-stable
     * mysql-4.0.18-win.zip
Installed both of these in folder MySQL.
I modified this line in the program ("ExecuteSQL" 1st pgm in chapter 17) I got from "Java Examples In a Nutshell" and compiled it into directory jwork.
String driver = "com.mysql.jdbc.driver", url = "jdbc:mysql://", user = "", password = "";
The readme file talks about putting a jar file in $JAVA_HOME/jre/lib/ext.
the word "Java_Home" (I now know) is not literally the name but represents the
name of the folder where the JDK to be used exists. So I put a copy of
mysql-connector-java-3.0.11-stable-bin.jar in folder C:\JDK14/jre/lib/ext.
Then I get a ClassNotFoundException error com.mysql.jdbc.driver.
After finding
http://forum.java.sun.com/thread.jsp?forum=31&thread=439796
and
http://forum.java.sun.com/thread.jsp?forum=31&thread=499888
and others, I copied (a second copy) the jar file to the directory where I am create my java objects.
Then I unzipped it to that directory, creating three folders that hold the unzipped objects.
I tried executing the program again. I get the messages at the top of this post.
The Manifest file is in one of the three folders unzipped to my java work directory.
In the second of the two above threads, jsalonen says:
the problem can be solved by mentioning mysql.jar in the Class-Path attribute
in the manifest of the jar file:
In this "manifest" file, there are only three lines and I added a fourth and it looks like this
(there are two, one in directory MySQL\META-INF and one in directory jwork\META-INF:
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.6.1
Created-By: 1.4.0_01-b03 (Sun Microsystems Inc.)
Main-Class:jwork\ExecuteSQL
How do I "mention" mysql.jar in the class path attribute?
In the index.list file (in the directory with the manifest file, do I need to add anything to refer that "com.mysql.jdbc.driver" is the driver?
Do I need index.list in MySQL\META-INF ?
Thank you for your help. The program ExecuteSQL follows.
* Copyright (c) 2000 David Flanagan. All rights reserved.
* This code is from the book Java Examples in a Nutshell, 2nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book (recommended),
* visit http://www.davidflanagan.com/javaexamples2.
/** package com.davidflanagan.examples.sql; */
import java.sql.*;
import java.io.*;
* A general-purpose SQL interpreter program.
public class ExecuteSQL {
public static void main(String[] args) {
Connection conn = null; // Our JDBC connection to the database server
try {
String driver = "com.mysql.jdbc.driver", url = "jdbc:mysql://",
user = "", password = "";
// Parse all the command-line arguments
for(int n = 0; n < args.length; n++) {
if (args[n].equals("-d")) driver = args[++n];
else if (args[n].equals("-u")) user = args[++n];
else if (args[n].equals("-p")) password = args[++n];
else if (url == null) url = args[n];
else throw new IllegalArgumentException("Unknown argument.");
// The only required argument is the database URL.
if (url == null)
throw new IllegalArgumentException("No database specified");
// If the user specified the classname for the DB driver, load
// that class dynamically. This gives the driver the opportunity
// to register itself with the DriverManager.
if (driver != null) Class.forName(driver);
// Now open a connection the specified database, using the
// user-specified username and password, if any. The driver
// manager will try all of the DB drivers it knows about to try to
// parse the URL and connect to the DB server.
conn = DriverManager.getConnection(url, user, password);
// Now create the statement object we'll use to talk to the DB
Statement s = conn.createStatement();
// Get a stream to read from the console
BufferedReader in =
          new BufferedReader(new InputStreamReader(System.in));
// Loop forever, reading the user's queries and executing them
while(true) {
System.out.print("sql> "); // prompt the user
System.out.flush(); // make the prompt appear now.
String sql = in.readLine(); // get a line of input from user
// Quit when the user types "quit".
if ((sql == null) || sql.equals("quit")) break;
// Ignore blank lines
if (sql.length() == 0) continue;
// Now, execute the user's line of SQL and display results.
try {
// We don't know if this is a query or some kind of
// update, so we use execute() instead of executeQuery()
// or executeUpdate() If the return value is true, it was
// a query, else an update.
boolean status = s.execute(sql);
          // Some complex SQL queries can return more than one set
          // of results, so loop until there are no more results
do {
if (status) { // it was a query and returns a ResultSet
ResultSet rs = s.getResultSet(); // Get results
printResultsTable(rs, System.out); // Display them
else {
// If the SQL command that was executed was some
// kind of update rather than a query, then it
// doesn't return a ResultSet. Instead, we just
// print the number of rows that were affected.
int numUpdates = s.getUpdateCount();
System.out.println("Ok. " + numUpdates +
                         " rows affected.");
// Now go see if there are even more results, and
// continue the results display loop if there are.
status = s.getMoreResults();
} while(status || s.getUpdateCount() != -1);
// If a SQLException is thrown, display an error message.
// Note that SQLExceptions can have a general message and a
// DB-specific message returned by getSQLState()
catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage()+ ":" +
                    e.getSQLState());
// Each time through this loop, check to see if there were any
// warnings. Note that there can be a whole chain of warnings.
finally { // print out any warnings that occurred
          SQLWarning w;
for(w=conn.getWarnings(); w != null; w=w.getNextWarning())
System.err.println("WARNING: " + w.getMessage() +
                         ":" + w.getSQLState());
// Handle exceptions that occur during argument parsing, database
// connection setup, etc. For SQLExceptions, print the details.
catch (Exception e) {
System.err.println(e);
if (e instanceof SQLException)
System.err.println("SQL State: " +
                    ((SQLException)e).getSQLState());
System.err.println("Usage: java ExecuteSQL [-d <driver>] " +
               "[-u <user>] [-p <password>] <database URL>");
// Be sure to always close the database connection when we exit,
// whether we exit because the user types 'quit' or because of an
// exception thrown while setting things up. Closing this connection
// also implicitly closes any open statements and result sets
// associated with it.
finally {
try { conn.close(); } catch (Exception e) {}
* This method attempts to output the contents of a ResultSet in a
* textual table. It relies on the ResultSetMetaData class, but a fair
* bit of the code is simple string manipulation.
static void printResultsTable(ResultSet rs, OutputStream output)
     throws SQLException
// Set up the output stream
PrintWriter out = new PrintWriter(output);
// Get some "meta data" (column names, etc.) about the results
ResultSetMetaData metadata = rs.getMetaData();
// Variables to hold important data about the table to be displayed
int numcols = metadata.getColumnCount(); // how many columns
String[] labels = new String[numcols]; // the column labels
int[] colwidths = new int[numcols]; // the width of each
int[] colpos = new int[numcols]; // start position of each
int linewidth; // total width of table
// Figure out how wide the columns are, where each one begins,
// how wide each row of the table will be, etc.
linewidth = 1; // for the initial '|'.
for(int i = 0; i < numcols; i++) {             // for each column
colpos[i] = linewidth; // save its position
labels[i] = metadata.getColumnLabel(i+1); // get its label
// Get the column width. If the db doesn't report one, guess
// 30 characters. Then check the length of the label, and use
// it if it is larger than the column width
int size = metadata.getColumnDisplaySize(i+1);
if (size == -1) size = 30; // Some drivers return -1...
     if (size > 500) size = 30; // Don't allow unreasonable sizes
int labelsize = labels.length();
if (labelsize > size) size = labelsize;
colwidths[i] = size + 1; // save the column the size
linewidth += colwidths[i] + 2; // increment total size
// Create a horizontal divider line we use in the table.
// Also create a blank line that is the initial value of each
// line of the table
StringBuffer divider = new StringBuffer(linewidth);
StringBuffer blankline = new StringBuffer(linewidth);
for(int i = 0; i < linewidth; i++) {
divider.insert(i, '-');
blankline.insert(i, " ");
// Put special marks in the divider line at the column positions
for(int i=0; i<numcols; i++) divider.setCharAt(colpos[i]-1,'+');
divider.setCharAt(linewidth-1, '+');
// Begin the table output with a divider line
out.println(divider);
// The next line of the table contains the column labels.
// Begin with a blank line, and put the column names and column
// divider characters "|" into it. overwrite() is defined below.
StringBuffer line = new StringBuffer(blankline.toString());
line.setCharAt(0, '|');
for(int i = 0; i < numcols; i++) {
int pos = colpos[i] + 1 + (colwidths[i]-labels[i].length())/2;
overwrite(line, pos, labels[i]);
overwrite(line, colpos[i] + colwidths[i], " |");
// Then output the line of column labels and another divider
out.println(line);
out.println(divider);
// Now, output the table data. Loop through the ResultSet, using
// the next() method to get the rows one at a time. Obtain the
// value of each column with getObject(), and output it, much as
// we did for the column labels above.
while(rs.next()) {
line = new StringBuffer(blankline.toString());
line.setCharAt(0, '|');
for(int i = 0; i < numcols; i++) {
Object value = rs.getObject(i+1);
          if (value != null)
          overwrite(line, colpos[i] + 1, value.toString().trim());
overwrite(line, colpos[i] + colwidths[i], " |");
out.println(line);
// Finally, end the table with one last divider line.
out.println(divider);
out.flush();
/** This utility method is used when printing the table of results */
static void overwrite(StringBuffer b, int pos, String s) {
int slen = s.length(); // string length
int blen = b.length(); // buffer length
if (pos+slen > blen) slen = blen-pos; // does it fit?
for(int i = 0; i < slen; i++) // copy string into buffer
b.setCharAt(pos+i, s.charAt(i));

Answer 1

Don't put those JARs in the lib/ext directory. Only language extensions (e.g., packages that start with "javax") belong in there.
Learn how to set the CLASSPATH properly for starters:
http://java.sun.com/j2se/1.4.2/docs/tooldocs/windows/classpath.html
You might want to look at the JDBC tutorial, too:
http://java.sun.com/docs/books/tutorial/jdbc/
Do one thing at a time. Get the program to work, then worry about packaging it into an executable JAR.