I have built a small program for school that runs perfectly when i run it through eclipse, but if I run the same code in NetBeans I get this error:
java.lang.NoClassDefFoundError: myrunnable/Main
Caused by: java.lang.ClassNotFoundException: myrunnable.Main
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
Could not find the main class: myrunnable.Main. Program will exit.
Exception in thread "main" Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)
How do i fix this?!
I have not used netbeans but from what I can see from your exception looks to me JRE may not be in the classpath. Have you checked that? For example when you create a project in eclipse it will automatically add JRE to the classpath.
OR
may be you need to explicitly compile/build before you can run. In eclipse it is auto too. When you run a simple.java it would have created the corresponding simple.class in the bin output folder.
Check those two areas you will be fine I think
Is there a main method defined in the class?
public static void main(String[] args) {
}
Also, is your Java JDK properly registered inside Netbeans?
Related
I created a Java project in Eclipse and created a simple class with a main method.
Problem: when I run the program(without any server etc), I get the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/codec/DecoderException
at autoPEC.main(autoPEC.java:6)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.codec.DecoderException
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
... 1 more
What I tried to solve the problem: included path to commons-codec.jar in the environment variables JAVA_HOME by putting a semicolon after the jdk path
Result: class still does not run
I think that the problem could be that I am not correctly including the classpath. How should I do this?
Google the missing jar and include it in the Java Build path
Reason for this exception is missing of a jar.
please add the jar(Commons-codec.jar) file needed for this org.apache.commons.codec.DecoderException
Download it from here
http://commons.apache.org/proper/commons-codec/download_codec.cgi
then put it in your classpath
I am getting the following error
Exception in thread "main" java.lang.NoClassDefFoundError: org/jsoup/Jsoup
at Main.main(Main.java:42)
Caused by: java.lang.ClassNotFoundException: org.jsoup.Jsoup
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 1 more
Now what I have done so far:
I created a libs folder in my project folder and added the Jsoup.jar there. Then in eclipse I click properties, add external Jar and added it. I see the referenced library.
But the issue still persist. I dont get compilation errors. So this is a runtime issue. Appreciate the help.
Edit:
I have found the following
If I compile using
javac -classpath /path/to/jsoup.jar myclass.java
and then
java -classpath /path/to/jsoup.jar myclass
It runs perfect.
Now. This is not working for me because I am going to use my application on a computer that does not have Jsoup. So how to I resolve this runtime issue?
Go to Run configurations... menu and check classpath for Run task. It looks like you add library for Compilation step, but it doesn't set at Run step.
Edit (after comment)
I dove into the issue and found that this dependency is needed for application container. So you just need to add this library to classpath of your app server. If you use Tomcat, just put the library to the %CATALINA_HOME%\lib directory.
I'm trying to check some SNMP example, so
i've downloaded snmp4j.jar
compiled SNMP.java using javac -cp snmp4j.jar SNMP.java (it's OK)
tried to start it using java -cp snmp4j.jar SNMP, but
it reports:
root#comp:~/workspace_c/SNMP# java -cp snmp4j.jar SNMP
Exception in thread "main" java.lang.NoClassDefFoundError: SNMP
Caused by: java.lang.ClassNotFoundException: SNMP
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
Could not find the main class: SNMP. Program will exit.
UPDATE:
And when I import snmp4j.jar to the java project, it works normally in ECLIPSE...
UPDATE#2: main part of SNMP.java
import org.snmp4j.CommunityTarget;
...
public class SNMP {
public static void main(String[] args) {
...
}
}
what i'm doing wrong? it's first time i've met snmp4j so i know noting about it
If I understand correctly, SNMP is your example class, which isn't inside the jar. In that case, you need to add to the classpath both the jar and your current directory:
java -cp .:snmp4j.jar SNMP
As far as I can see you are trying to run your application with SNMP4J.jar (upper case) but when you compiled your application you probably used lower case version.
Your prompt shows that your are using unix OS that has case sensitive file system. So, check the case of the JAR file name. I believe that all letters are in lower case.
I'm trying to create a simple Java Agent program before I implement the real thing. I cannot get it to run. Clearly I have some sort of configuration or class path problem. No amount of looking and trying has lead to me the problem.
If I run:
java -cp ./demoAgent.jar -javaagent:./demoAgent.jar com.kingtigerbooks.demoMod.Main
I get the following error:
Exception in thread "main" java.lang.ClassNotFoundException: com.kingtigerbooks.demoAgent.Agent
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)
at sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:280)
at sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:338)
FATAL ERROR in native method: processing of -javaagent failed
Abort trap
I'm running this on my Mac. The jar file with the agent is in the current directory. The manifest for the jar file looks like this:
Manifest-Version: 1.0
Premain-class: com.kingtigerbooks.demoAgent.Agent
Can-Redefine-Classes: true
If smells like a class path problem, but as you can see I have included the jar on the class path. Any help would be appreciated. Its a very simple project.
Problem solved. I had a bad jar file. The agent jar file did not contain the agent class. By building the correct jar file and putting the fully qualified path to the jar on in the javaagent parameter it all works.
when you run an agent, you do not add the agent jar to the normal classpath.
as a side note, you can add -verbose:class to the command line to get info about the class loading process.
The program is written with 2 files filter.java - in which is the main function and ClasifiedWord.java which is only container class. I wrote that on windows on eclipse but want to compile it on Linux javac compiler.
javac filter.java ClasifiedWord.java
runs without mistakes, but when I try to run the program:
snowy:Filter$ java filter
Exception in thread "main" java.lang.NoClassDefFoundError: filter
Caused by: java.lang.ClassNotFoundException: filter
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)
Could not find the main class: filter. Program will exit.
snowy:Filter$ javac filter.java ClasifiedWord.java
snowy:Filter$ java filter ClasifiedWord
Exception in thread "main" java.lang.NoClassDefFoundError: filter
Caused by: java.lang.ClassNotFoundException: filter
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)
Could not find the main class: filter. Program will exit.
How can I run the program ? It seems that the compilation is ok. I have doubts that maybe I have made a mistake about the file paths in the program.... but I think that this is not the case?
Thanks for your answers!
Type the following command.
java -classpath . filter
If you want to type just java filter, please following these guides.
Linux http://www.cyberciti.biz/faq/linux-unix-set-java_home-path-variable/
Windows http://ac-support.europe.umuc.edu/~arnoldyl/NetBeansTutorials/Setting-Classpath.html
P.S. The last command java filter ClasifiedWord means to run a program filter and use a string ClasifiedWord as an argument.
Roland is right in the comment, you should be able to run it with java -classpath <folderContainingDotClassFiles> filter. Also, you should change filter.java to Filter.java as the standard Java convention for class names (including the files containing them) is to capitalize the first letter.
This looks like you either have a wrong CLASSPATH setting (usually you don't need this at all, but if you have it, it should include . in the list, for the current directory), or you are using packages (wrongly), or both. For the classpath issue, see the other answers.
If you are using packages, i.e. your files contain a package ...; line at the beginning, you should put your source files in a directory structure according to the package structure. For example, if you have package example;, you should have an example directory in your current directory, and in this the two source files.
Then call compiler and interpreter like this:
javac example/filter.java example/ClasifiedWord.java
java example.filter
(This assumes that filter is the main class, otherwise replace its name.)