Apache HttpClient抛出NoClassDefFoundError

Question

I have: ubuntu-9.10-desktop-amd64 + NetBeans6.7.1

1. I just downloaded "Commons HttpClient 3.1 (legacy)" from http://hc.apache.org/downloads.cgi .
2. I created new application with IDE NetBeans.
3. I focused on Projects -> Libraries -> Add JAR/Folder and here added commons-httpclient-3.1.jar
4. By now, I can write "import org.apache.commons.httpclient.*;" This is OK.

5. But, if I try to add any statement included something like this:

    public static void main(String[] args) { HttpClient client = new HttpClient(); } 

6. It is compiled well.

7. But when I run this project, I receive the following errors:

    ***Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory at org.apache.commons.httpclient.HttpClient.<clinit>(HttpClient.java:66) at SimplestAppl.Main.main(Main.java:22) Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory at java.net.URLClassLoader$1.run(URLClassLoader.java:217) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at java.lang.ClassLoader.loadClass(ClassLoader.java:319) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) at java.lang.ClassLoader.loadClass(ClassLoader.java:264) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:332) ... 2 more Java Result: 1*** 

What is wrong?

I tried to download "HttpClient 4.0 (GA)". But the result was same.

Answer 1

What you are experiencing is just a missing dependency. Java developers are used to gather their dependencies themselves, esp. when it comes to logging frameworks. Download commons-logging and add it to your classpath. Do as well with all other dependencies required by httpclient.

Answer 2

You need the dependencies. If you used maven, they would fetch themselves. Since you aren't, you've got to go download commons-logging (and perhaps others) and toss them in.

Answer 3

I'd like to update anyone coming here to the fact that all answers, and especially RocketSurgeon's, helped me solve my issue in the same sense. I had to download commons httpclient (legacy 3.1), logging and codec before my issues were resolved.

Also of note; using Eclipse I had to extract the .jar-files and import them into Buildpath using "add library". Did not work with only adding .zip-file.

Answer 4

If you dont want to use Maven, then

- build and launch, look at missing dependencies
- identify vendor, fetch the jar to resolve dependencies
- rinse/repeat until you have all dependencies satisfied
- done

anyway you will be never sure if all dependencies are 100% supplied. Its usually around 150% or 99%, but never in between