Develop Reference

Getting 'Exception in thread "main" java.lang.NoClassDefFoundError: org/ini4j/Ini' error after succesfully compiling source file from the CLI

Background:
I am trying to use ini4j for the purpose of parsing config files in the ini format.
I run the command:
javac -classpath ini4j-0.5.4.jar Driver.java
and the compilation goes smoothly...however when I attempt to run the program running:
java Driver
I get this error:
Exception in thread "main" java.lang.NoClassDefFoundError: org/ini4j/Ini
at Clock.main(Clock.java:13)
Caused by: java.lang.ClassNotFoundException: org.ini4j.Ini
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 1 more
From what I understand this error is a product of the jvm being able to find the class file being referenced in the error and failing. I checked the ini4j jar file and confirmed that the Ini.class file does in fact exist. Can anyone please tell me what am I missing here ?
The following is my source code:
import java.util.Map;
import java.io.IOException;
import java.io.File;
import org.ini4j.* ;
public class Driver{
public static void main(String[] args){
System.out.println("running in Clock-J main()");
String fileName = "./test.ini" ;
File fileObject = new File(fileName);
try{
Ini ini = new Ini(fileObject);
}catch(IOException e){
String exception = e.toString() ;
e.printStackTrace();
}
}
}

You also need to specify the -classpath option when you run the program. Java will not automatically pick up the jar files that you passed when you compiled your code.

The correct answer for my situation appears to be:
java -cp .:ini4j-0.5.4.jar Driver
Thanks for pointing me in the correct direction guys!!!! Using an IDE causes one to forget stuff like this. I really appreciate it!!!! Thanks!!!!!

Look at Elipse->Properties->JavaBuildPath->Libraries
list of extended JARs have to be in CLASSPATH
please check for more info

Unsure about reason behind NoClassDefFoundError

I have built a DLL which I am attempting to wrap Java code with, however I am having some troubles with running my Java program. I wrote a simple test DLL and Java program and am producing the same error, and although there are plenty of resources regarding NoClassDefFoundError online I can't seem to solve mine with any troubleshooting methods.
Here is my D:\Test1.Java file
public class Test1 {
static {
//System.loadLibrary("HeyLand");
System.load("D://HeyLand.dll");
}
public native void displayHeyLand();
public static void main (String[] args) {
Test1 t = new Test1();
t.displayHeyLand();
}
}
After compiling, attempting to run D:\Test1.classresults in the following:
D:\>java Test1.class
Exception in thread "main" java.lang.NoClassDefFoundError: Test1.class
Caused by: java.lang.ClassNotFoundException: Test1.class
at java.net.URLClassLoader.findClass(URLClassLoader.java:434)
at java.lang.ClassLoader.loadClass(ClassLoader.java:660)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:358)
at java.lang.ClassLoader.loadClass(ClassLoader.java:626)
Could not find the main class: Test1.class. Program will exit.
Why I am stumped :
1. I have set my classpath to be D:\, so I believe my class definition would be in the classpath, and I do not see how my compile-time and run-time classpaths could be any different.
2. I don't see how this could have anything to do with static initialization, and I believe the exception would look different.
Perhaps I'm just missing something incredibly simple, I am very newbie with Java.
Any help is greatly appreciated!

The classpath environmental variable is taking precedence over that in the java run command. You need to specify the class location (as well as removing the .class file extension)
java -cp . Test1

Java normal syntax for executing class file is
Java [<options>....} <class-name> [<arguments>....]
For example
java com.package.name.Test1
here how compiler works
1. Compiler search for complete class name
2. Load that class
3. check for main method - in the same class
4. Call main method with passed arguments in command line string.
Now following are the possibilities why your class may not found main method.
1 - forgot to include package name
I am new developer in java but I found when I run application using eclips or intellJ editor it gives different path and package name and execute code as I noticed it on command line edior. So make sure you are including package name
For example:
java com.package.name.Test1 instead of
java Test1
2. File name or pathname rather then class name
As I noticed output file is in different location. That why class file path was different.
java Test1.class
java com/package/name/Test1.class
3. Typo
also I noticed you are using
static {
//System.loadLibrary("HeyLand");
System.load("D://HeyLand.dll");
}
Is this function ? or constructor? If it is function then where is name of the function? You cant write code without any reference in classs

Java -> including robot class in eclipse

I would like to work with this robot class :
http://docs.oracle.com/javase/1.5.0/docs/api/java/awt/Robot.html
for generating native system input´s, thats why i created this file:
import java.awt.Robot;
public class MouseClass {
public static void main(String[] args) throws Exception {
Robot robot = new Robot();
// SET THE MOUSE X Y POSITION
robot.mouseMove(300, 550);
}
}
but i got this error-msg:
Exception in thread "main" java.lang.NoClassDefFoundError: robot/robot_v1
Caused by: java.lang.ClassNotFoundException: robot.robot_v1
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
I thought, the awt.robot is already integrated in eclipse? ok if not..i dont know where to download this robot-class, the only page i found is:
http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/java/awt/Robot.java
but thats "Robot.java" and the error-message doent change when i include this in my "src".
Any advices how i can use this robot-class?
SOLVED ,but:
i get a compilation problem
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
at robot.robot_v1.main(robot_v1.java:5)
For this line:
public static void main(String[] args) throws Exception {
do i have to change name´s here as well in this case?
greetings
=> SOLDED with package robot;

Your issue is not related to Robot class at all. There is mismatch between your java file name and class name.
Your java class as you meantion in comment is robot/robot_v1.java and your class name is MouseClass. To make it work, all what you need to do is change your class name to be same as file which will be robot_v1 and as it is not in default package, you need to add at beginning of your file package definition, which will be for this case package robot;

When running Eclipse, I am getting a error in console after running the code

So am literally taking a intro to Java Programming and now I am trying to create my second assignment. Upon doing so I have created the new java class within eclipse, but when I try to run the code that I have written, I am getting the following errors.
I am not real sure on how to fix this. Any assistance would be greatly appreciated.
Exception in thread "main" java.lang.NoClassDefFoundError: math
Caused by: java.lang.ClassNotFoundException: math
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

ClassNotFoundException: math
I'm guessing you created a class with a capital M in math, but when you call it somewhere, it's not capitalized, or referenced properly. Try to double check that in your code.
Friendly FYI for proper Java standards, try to make sure that classes are capitalized.

You said your code is the following:
public class rounding {
public static void main (string[] args){
System.outprintln("Hello World");
From the error message you received, you most likely have this code in a file named math.java. In Java, you must declare the class name as equal to the file name; for example, YourClass.java would declare public class YourClass {.
So what you need to do is either rename your class name to math, or name your file rounding.java, although it is unconventional to begin class names with a lower case letter.
On top of these errors however, you'll run into an error saying that the type string does not exist. You need to rename that the type string[] to String[] or the JVM won't be able to identify your main method.
You will also receive an error saying that outprintln is not a method of the System class. To print, use System.out.println("Your message") rather than System.outprintln("Your message").

It sounds like you're trying to access a class called "math" that does not exist in your current project or scope. Did you forget to import a particular library that you're supposed to be using?

This is the correct code:
public class Rounding {
public static void main (String[] args){
System.out.println("Hello World");
}
}
Some minor bugs which is usually done by all who start out with Java and Eclipse. The description of the error has already been given by Vulcan.

OpenGL in Java on Netbeans: NoClassDefFoundError

I am on a Mac running Netbeans 6.9.
I downloaded and installed LWJGL using this tutorial down to the letter:
http://lwjgl.org/wiki/index.php?title=Setting_Up_LWJGL_with_NetBeans
I finished the installation and copied sample code to see if my system is working. I got a bug, and was not sure if it was because of faulty code or I was doing something wrong. So I shortened down the code to this little simple bit:
package javaopengl;
import org.lwjgl.Sys;
import org.lwjgl.opengl.Display;
//Testing
public class Main {
public static void main(String[] args) {
boolean fullscreen = (args.length == 1 && args[0].equals("-fullscreen"));
try {
Display.create();
Display.destroy();
} catch (Exception e) {
e.printStackTrace(System.err);
}
System.exit(0);
}
}
But I still get the same error:
run:
Exception in thread "main" java.lang.NoClassDefFoundError: =
Caused by: java.lang.ClassNotFoundException: =
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)
I am not sure what exactly is going on, Would you please tell me what is going on and how to fix it?
Note: When i am looking at the text in the development environment, it does not show those red lines indicating there are any errors.

What are you typing (or what is netbeans running) to run this? Since the Mac filesystem is fairly case-agnostic unless you've specified otherwise, running java javaopengl.main will look for a file main.java, which is there (Main.java will be returned). But the class is Main, and you can get this exception from the difference. If this is being run from an ant script, I suggest making sure you have the correct capitalization (the class should be javaopengl.Main). A simple way to test this is to delete everything except the class definition and an empty public static void main(String[] args) {}
Alternatively, you could have something simpler, like your classpath out of whack. Missing the lwjgl jar would get you there, but if you followed the directions in that tutorial, that actually seems less likely. Still, you can test this.
package javaopengl;
public class Main {
public static void main(String[] args) {
System.out.println("well, main works");
Class checkjar = Class.forName("org.lwjgl.opengl.Display");
System.out.println("My ClassLoader found: " + checkjar.getCanonicalName());
}
}
Also, remove import org.lwjgl.Sys; from your shortened example. It doesn't appear to be needed, provided it isn't the source of your problems :).