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java.lang.NoClassDefFoundError when trying to instantiate class from jar

I did found quite a lot about this error, but somehow none of the suggested solutions resolved the problem.
I am trying to use JNA bindings for libgphoto2 under Ubuntu in Eclipse (moderate experience with Java on Eclipse, none whatsoever on Ubuntu, I'm afraid). The bindings in question I want to use are here:
http://angryelectron.com/projects/libgphoto2-jna/
I followed the steps described on that page, and made a simple test client that failed with the above error. So I reduced the test client until the only thing I tried to do was to instantiate a GPhoto2 object, which still produced the error. The test client looks like this:
import com.angryelectron.gphoto2.*;
public class test_class
{
public static void main(String[] args)
{
GPhoto2 cam = new GPhoto2();
}
}
The errors I get take up considerably more space:
Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/jna/Structure
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at test_class.main(test_class.java:12)
Caused by: java.lang.ClassNotFoundException: com.sun.jna.Structure
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 13 more
libgphoto2 itself is installed, it runs from the command line, I even have the development headers and am able to call GPhoto2 functions from python, so the problem can't be located there.
When looking at the .class files in Eclipse, however, they didn't have any definitions. So I figured that might be the problem, especially since there was an error when building the whole thing with ant (although the .jar was succesfully exported, from what I could make out the error concerned only the generation of documentation).
So I loaded the source into eclipse and built the .jar myself. At this occasion Eclipse stated there were warnings during the build (though no errors), but didn't show me the actual warnings. If anyone could tell me where the hell the build log went, that might already help something. I searched for it everywhere without success, and if I click on "details" in eclipse it merely tells me where the warnings occured, not what they were.
Be that as it may, a warning isn't necessarily devastating, so I imported the resulting Jar into the above client. I checked the .class files, this time they contained all the code. But I still get the exact same list of errors (yes, I have made very sure that the old library was removed from the classpath and the new ones added. I repeated the process several times, just in case).
Since I don't have experience with building jars, I made a small helloworld jar, just to see if I could call that from another program or if I'd be getting similar errors. It worked without a hitch. I even tried to reproduce the problem deliberately by exporting it with various options, but it still worked. I tried re-exporting the library I actully need with the settings that had worked during my experiment, but they still wouldn't run. I'm pretty much stuck by now. Any hints that help me resolve the problem would be greatly appreciated.

In addition to what #Paul Whelan has said. You might have better luck by just get the missing jar directly.
Get the missing library here, set the classpath and then re-run the application again and see whether it will run fine or not.

What version of java are you using com/sun/jna/Structure may only work with certain JVMs.
In general, packages such as sun., that are outside of the Java platform, can be different across OS platforms (Solaris, Windows, Linux, Macintosh, etc.) and can change at any time without notice with SDK versions (1.2, 1.2.1, 1.2.3, etc). Programs that contain direct calls to the sun. packages are not 100% Pure Java.
More details here

Your jar needs a MANIFEST.MF which tells your application where the library is found. Create the file in you project root-directory in eclipse and add the following lines:
Manifest-Version: 1.0
Class-Path: <PATH_TO_LIB__CAN_BE_RELATIVE>.jar // e.g Class-Path: ../test.jar
<empty line>
Right-click your project in eclipse, go to Export->next->next->next->Use existing manifest from workspace, select it and click on finish. This should work.
Another solution is to compile the classes into the jar itself with Maven.

How to identify the dependent libraries I need

I am building a little something in Java that uses Wolfram|Alpha to come up with integrals. I downloaded the Wolfram API and it comes with a sample program that you can use to figure stuff out. Here's that at GitHub.
There's a portion in the comments that says:
* To compile or run this program you will need the following dependent
* libraries on your classpath (including WolframAlpha.jar, of course):
*
* commons-codec-1.3.jar
* httpclient-4.0.1.jar
* httpcore-4.0.1.jar
* commons-logging.jar
... and I have no idea how to do this. I'm using this project as a way to learn Java, so I am skipping a bunch of sleep-inducing fundamentals.
Are these libraries available in the vanilla Java install, or do I have to go fetch them from elsewhere? I want to avoid loading up my system with redundant stuff.
When I try to run the script without loading these libraries it ends in an error, predictably. Here's the error message:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/conn/scheme/SocketFactory
at com.wolfram.alpha.net.HttpProviderFactory.getDefaultHttpProvider(HttpProviderFactory.java:18)
at com.wolfram.alpha.WAEngine.<init>(WAEngine.java:36)
at simpleSample.main(simpleSample.java:58)
Caused by: java.lang.ClassNotFoundException: org.apache.http.conn.scheme.SocketFactory
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)
... 3 more
I am using Eclipse as my IDE. I don't think it matters here, but it might.

#dimplex has already answered. These are releases of several Apache projects. Next time you meet these problems, try:
Google:
Like:
Google commons-codec-1.3.jar
Google httpclient-4.0.1.jar
Google httpcore-4.0.1.jar
Google commons-logging.jar
The first result for EVERY search above is a couple clicks away from the download you're looking for.
Maven Central Search:
http://search.maven.org
(I'm not copying every link, just search for the Jar file names.)
This one is even more direct, but I'd recommend the Google way, as you can get a glimpse of the project page.

You have to upgrade the httpclient.jar to version 4.1.
As you can see in the javadoc theses class available from this version

These are all (old) Apache Software Foundation libraries. The download locations are as follows:
commons-codec-1.3.jar
httpclient-4.0.1.jar
commons-logging.jar
httpcore-4.0.1.jar

JOGL Opengl WriteCloneable in eclipse

I am following this tutorial.
Although I did exactly same as the tutorial, even i watched the video.
Even i tried other tutorial.But all of my try, i got that error everytime.
When i click to run, a error box display and "A Java Exception has occurred."
And i see that errors in consol
Exception in thread "main" java.lang.NoClassDefFoundError: com/jogamp/common/type/WriteCloneable
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
...
Even i uninstalled jdk&jre and i download last version and install.
I am using eclipse, Windows 7 home premium 64 bit.

At first, his tutorials contain several errors, I already complained in the comments of his Youtube video. I advise you to use the official tutorials in our wiki and to contact us on the official forum if you need some help.
Something was probably wrong in your environment or you used the 32 bits version with a 64 bits JVM. If you don't know which JARs you should use for the native libraries, just take the both and let GlueGen pick the right one.

Make sure you add all the 4 libs in your project, like this.
-lib
--gluegen-rt.jar
--gluegen-rt-natives-windows-amd64.jar
--jogl-all.jar
--jogl-all-natives-windows-amd64.jar
That works to me:)

Looks like a problem with your classpath since the WriteCloneable class isn't being found - one or more of the jars that you need is probably missing from the build path.
In Eclipse: Right click on your project / Properties / Java Build Path / Libraries tab. Check that the JOGL libraries that you need are all there.

Had the same problem. I solved it by adding the dependencies for gluegen. First I only had:
<dependency>
<groupId>org.jogamp.jogl</groupId>
<artifactId>jogl-all-main</artifactId>
<version>2.3.2</version>
</dependency>
this solved the problem:
<dependency>
<groupId>org.jogamp.gluegen</groupId>
<artifactId>gluegen-rt-main</artifactId>
<version>2.3.2</version>
</dependency>

I find solution.
If you get JVMUtil or WriteCloneable error with NoClassDefFoundError, you must copy that 4 library jar to java/jre/lib/ext folder.
thanks for schabby.

How to use xstream fro xml serialization in eclipse

I am having some trouble figuring out how to download and use xstream in eclipse. When I download the binary distribution from the website, I get a zip file. Where should I extract it, and how do I use it?
Edit:
OK, I have added it to my build path, but now when I try to use XStream to serialize an ArrayList<Earmark> where Earmark is a class that I have defined, I get the following error message:
Exception in thread "main" java.lang.NoClassDefFoundError: org/xmlpull/v1/XmlPullParserException
at com.thoughtworks.xstream.XStream.<init>(XStream.java:334)
at examples.TestEarmarkExtractor.SerializeEarmarks(TestEarmarkExtractor.java:19)
at examples.TestEarmarkExtractor.main(TestEarmarkExtractor.java:48)
Caused by: java.lang.ClassNotFoundException: org.xmlpull.v1.XmlPullParserException
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)
... 3 more
Update: The error is occurring before I try the serialization. It occurs on the line
XStream xs = new XStream();

Extract the zip file to a directory (e.g. C:\Program Files\XStream)
In eclipse, right-click on your project and select Build Path > Configure Build Path...
Select Libraries tab
Select Add External Jars..
Navigate to the lib folder of your XStream download and select the jar(s) to be added
Select Open
Select OK
And here's the Two Minute Tutorial on how to use XStream.

Got this exception, then I download kxml2-min-2.3.0.jar and add it as a library and now it works (using xstream 1.4.4.jar)

You need to unzip the .zip file to get at the .jar file, which you put on your classpath for your project in eclipse (Google if you don't know how to add third party library .jars to your project classpath in Eclipse).
Once it is added to your project's classpath, you use the classes contained within it as you would any other classes, and the documentation on the XStream website tells you how to use them.
Good choice by the way, XStream is great!

You can add this library:
<dependency>
<groupId>xmlpull</groupId>
<artifactId>xmlpull</artifactId>
<version>1.1.3.1</version>
</dependency>

I had added the two libraries: dom4j-2.0.0-ALPHA-2.jar and xstream-1.4.7.jar and the same issue were displayed. After adding the kxml2-min-2.3.0.jar the issue is not happening.

Why Exception in thread "main" java.lang.NoClassDefFoundError:?

I run my software through Eclipse. Yesterday everything was fine. I made not changes to the code but today, when I am trying to run it again I get the following error messages:
Exception in thread "main" java.lang.NoClassDefFoundError: coloredtrails/CTListener
at test.DemoPlayer1.createAndShowGUI(DemoPlayer1.java:23)
at test.DemoPlayer1.main(DemoPlayer1.java:39)
Caused by: java.lang.ClassNotFoundException: coloredtrails.CTListener
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)
... 2 more
Why it does not see the class? What could be the reason of that? How can I resolve the problem?

A NoClassDefFoundError (almost) always means that your classpath is wrong. Make sure that your classpath includes the base directory of the coloredtrails package. (Ofcourse, also make sure that the file coloredtrails\CTListener.class actually exists).
When running from the command line:
You can set the classpath by setting the CLASSPATH environment variable, or by specifying it with the -cp or -classpath option on the command line when you run your program. For example:
java -cp C:\MyProject\classes coloredtrails.CTListener
edit - Looking at the stack trace and seeing URLClassLoader in there makes me think that you are trying to run a Java applet. To learn how to correctly deploy applets, so that all classes the applet needs can be found, see this tutorial: Deploying an Applet.

Sometimes, my Eclipse (Indigo on MacOSX) does that, expecially if I do changes (removing files, moving them around) to the project structure on the filsystem directly.
Basically, eclipse cannot find the source folder anymore, so he doesn't compile the source but tries to run it anyway (all this without a warning or a reference to the problem).
To fix it, remove the source folder from the build path (=right click on the src folder under the project in the package explorer, then choose "Build-path->Remove from Build-path". Then, add it again (=right click on the folder under the project in the package explorer and choose "Add to build-path"). This makes the src folder "visible" to the compiler again and fixes the problem.