Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

“NoClassDefFoundError” error

Posted on 2003-12-03
7
Medium Priority
?
260 Views
Last Modified: 2010-03-31
I am working on project that retrieve a web page and the images it contains to local storage, so that I can look at the web page loaded from our local file system; command-line application that takes two arguments: The first argument represents the download directory into which the web page will be downloaded and the second argument represents the absolute URL of the web page to download.

After compilation, all class files are located under c:\classes\dkim18\crawler\ and all source code are located under c:\src\dkim18\crawler\. When I run my program by typing “java WebCrawler c:\classes\dkim18\crawler\  http://webdev.apl.jhu.edu/%7Emed/index.html” under c:\classes\dkim18\crawler\ dir, I have “NoClassDefFounder” error. If I compile and run same way under c:\src\dkim18\crawler\ dir, my program works.

My question is that why do I have “NoClassDefFoundError” error when I run my program under c:\classes\dkim18\crawler\ and why my program runs under c:\src\dkim18\crawler\ dir?

Thanks,
0
Comment
Question by:dkim18
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
7 Comments
 
LVL 35

Expert Comment

by:TimYates
ID: 9865093
> When I run my program by typing “java WebCrawler c:\classes\dkim18\crawler\  http://webdev.apl.jhu.edu/%7Emed/index.html”

Why do you put the c:\classes...  bit in the command line?

What is the actual exception?

Sounds like you're not copying a class across to the classes dir...

java -cp . WebCrawler c:\classes\dkim18\crawler\  http://webdev.apl.jhu.edu/%7Emed/index.html
0
 
LVL 92

Accepted Solution

by:
objects earned 300 total points
ID: 9865114
think it should be:

java -classpath c:\classes dkim18.crawler.WebCrawler c:\classes\dkim18\crawler\  http://webdev.apl.jhu.edu/%7Emed/index.html
0
 
LVL 9

Assisted Solution

by:yongsing
yongsing earned 100 total points
ID: 9865120
You need to add c:\classes\dkim18\crawler\ to your CLASSPATH. You can add it in the command window:

SET CLASSPATH=%CLASSPATH%;c:\classes\dkim18\crawler
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 92

Expert Comment

by:objects
ID: 9865123
compiling is working so perhaps you already have c:\classes in your classpath so you can just do:

java dkim18.crawler.WebCrawler c:\classes\dkim18\crawler\  http://webdev.apl.jhu.edu/%7Emed/index.html

0
 
LVL 35

Assisted Solution

by:TimYates
TimYates earned 100 total points
ID: 9865127
oh yeah... bah...

hehehe

cd \classes
java -cp . dkim18.crawler.WebCrawler c:\classes\dkim18\crawler\  http://webdev.apl.jhu.edu/%7Emed/index.html

like objects and yongsing said...
0
 
LVL 92

Expert Comment

by:objects
ID: 9865251
if its not already there your life will be  alot easier if you ad c:\classes to classpath in System Properties.

Some bedtime reading on the classpath:
http://mindprod.com/jgloss/classpath.html
0
 
LVL 35

Expert Comment

by:TimYates
ID: 9865259
Hehehe, I love that page :-)
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

For beginner Java programmers or at least those new to the Eclipse IDE, the following tutorial will show some (four) ways in which you can import your Java projects to your Eclipse workbench. Introduction While learning Java can be done with…
Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
This tutorial will introduce the viewer to VisualVM for the Java platform application. This video explains an example program and covers the Overview, Monitor, and Heap Dump tabs.
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …
Suggested Courses

636 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question