I have a program that I run from Eclipse successfully.
However, when I want to run it from terminal, I encounter the famous error:
"java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver"
on this line:
Class drvClass = Class.forName("oracle.jdbc.driver.OracleDriver");
PS:
I have the following in CLASSPATH:
/oracle/jdbc/lib/ojdbc6.jar
Also note that I compile it successfully (javac Test2.java). Then when I run it (java Test2), I get the following error:
Error: Could not find or load main class Test2
So I run:
java -classpath ~/Desktop/JDBC2/src Test2
It runs, but I get the above "ClassNotFoundException" though.
I found this question tricky: the reason is related to semicolon after jar file address.
At first I changed the directory of MySample.java to another directory (you can don't do that) like C:\
then I removed package address from the source code, at the end I run this command in cmd
java -cp path_to_oracle_driver.jar; MySample
P.S. If you want run it from terminal you have to remove package PackageAddress from the source code and compile it again.
As #yngwietiger mentioned above in the comments, using -classpath parameter when running the .class file, overrides the original CLASSPATH and the predefined ojdbc6.jar file. So we need to mention both when running:
java -classpath ~/Desktop/JDBC2/src:/oracle/jdbc/lib/ojdbc6.jar Test2
Or, as a better solution, we can add the current path to CLASSPATH (note the colon and dot at the end):
export CLASSPATH=$CLASSPATH:.
And, in order to run, we just need to type:
Java Test2
I've a java script who's running by several user and working very well.
Today, I asked another user to try the script on his desktop and he's getting a ClassNotFoundException... despite the script is perfectly the same as mine (and jar locations is also the same)
Here's the command tu launch the JAR :
java -cp .;customname.jar;libs/* my.package.MyMainClass
And I also tried to add every jar in the libs folder separately :
java -cp .;customname.jar;libs/lib.jar;libs/lib2.jar;libs/lib3.jar my.package.MyMainClass
And here's the error message the user is getting :
Error: Could not find or load main class ch.vaudoise.hp.services.listener.AutoSysReorder
I checked the JAVA configuration and try to set him the same java version on "Path" environment variable. Same error.
As there's 6 user who can run the script and only one who's getting an error I'm sure it's a configuration issue. But what ? Classpath seems to be OK...
Many thanks for any help..
First things first: You must start by finding where is the conflicting class. If you don't know it, you may find it in two alternative ways:
Programatically: Code this class and execute it with the same classpath (on an environment that does not suffer the problem):
public static void main(String[] args)
{
System.out.println(ch.vaudoise.hp.services.listener.AutoSysReorder.class. getResource("/ch/vaudoise/hp/services/listener/AutoSysReorder.class"));
}
Manually, one by one: Open a command shell and execute:
javap -cp . ch.vaudoise.hp.services.listener.AutoSysReorder
javap -cp customname.jar ch.vaudoise.hp.services.listener.AutoSysReorder
javap -cp libs/lib.jar ch.vaudoise.hp.services.listener.AutoSysReorder
javap -cp libs/lib2.jar ch.vaudoise.hp.services.listener.AutoSysReorder
...
Try one by one every entry in the classpath until the class is found.
Once found the location of the class, open a shell in the conflicting PC and make sure that path is accessible:
dir lib\conflicting-library-or-directory
Also, repeat the javap test:
javap -cp conflicting-library-or-directory ch.vaudoise.hp.services.listener.AutoSysReorder
After this tests, you should have more clues to find the cause of the problem.
Take a look at ClassNotFoundException despite class in the classpath
You are also including meta character (*) in your classpath.
Try without that as suggested in the link.
Also some times copy pasting to command line , may get some characters copied differently.
I cannot add comment as of now : So , editing this answer.
| Java path is not an issue.
Try the following step by step :
- find which jar the class that is being not found is in .
- include only that jar as cp.
- include only that class and try
java -jar that.jar
Also try this once
java -cp "*;"
If you still got issue , probably the jar does not contain the class (You can open jar and check).
And you say script - is this single command which is failing or is it part of script ?. Using java -jar -cp , usually ignores cp.
This question seems to have been answered a few times (What does "Could not find or load main class" mean? and https://stackoverflow.com/a/16208709/2771315) but for some reason none of the shared methods are working.
What I've done so far.
1) Navigated to the directory containing the CoreNLP source files in terminal: ~/Downloads/CoreNLP-master/src
2) Selected one of the packages as a test case e.g. executed the command java -cp "*" -mx5g edu.stanford.nlp.sentiment.SentimentPipeline -file foo.txt (as per the docs, http://nlp.stanford.edu/sentiment/code.html)
I've tried variations of the above by altering the classpath -cp condition and setting it using set CLASSPATH = $CLASSPATH=~/Downloads/CoreNLP-master/src but can't seem to get a result. Does anyone know what I'm doing wrong? If I were to hazard a guess, I think that there is something wrong with the classpath but I'm not sure what.
The classpath should point to the classes, not the source files. If you're using the GitHub version of the code, you can set the classpath to be:
-cp ~/Downloads/CoreNLP-master/classes:/path/to/corenlp/models.jar
You can find the most recent version of the CoreNLP models at: http://nlp.stanford.edu/software/stanford-corenlp-models-current.jar (warning: >200MB file)
If you have one of the corenlp releases, you should set your classpath to:
-cp /path/to/corenlp.jar:/path/to/corenlp/models.jar
For example:
export CLASSPATH=stanford-corenlp-3.9.1.jar:stanford-corenlp-3.9.1-models.jar
Both the corenlp jar and the models jar should show up in the zipped release of the code (e.g., from http://nlp.stanford.edu/software/corenlp.shtml)
This worked perfectly fine for me.
java -cp "../*" -mx1g edu.stanford.nlp.sentiment.SentimentPipeline -file test.txt
Run this command while you are in the classes directory.
You are trying to run the program, instead of compiling it.
This question already has answers here:
What does "Could not find or load main class" mean?
(61 answers)
Closed 2 years ago.
I am running a simple "HelloWorld" Program. I get this error in the command prompt:
Could not find or load main class HelloWorld.
I have set the CLASSPATH and PATH variable in the system. In the cmd prompt, I am running from the directory where I have saved HelloWorld program. I can see the class name and the file name are same and also .class file created in the same directory. What else could be the problem?
My sample program looks like this:
package org.tij.exercises;
public class HelloWorld {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("Hello World!!");
}
}
When the Main class is inside a package then you need to run it as follows :
java <packageName>.<MainClassName>
In your case you should run the program as follows :
java org.tij.exercises.HelloWorld
What's your CLASSPATH value?
It may look like this:
.;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar
I guess your value does not contain this .;.
So, ADD IT .
When you done , restart CMD
That may works.
For example the file HelloWorld.java is in path: D:\myjavatest\org\yz\test and its package is: org.yz.test.
Now, you're in path D:\myjavatest\ on the CMD line.
Type this to compile it:
javac org/yz/test/HelloWorld.java
Then, type this to run it:
java org.yz.test.HelloWorld
You may get what you want.
I removed bin from the CLASSPATH. I found out that I was executing the java command from the directory where the HelloWorld.java is located, i.e.:
C:\Users\xyz\Documents\Java\javastudy\src\org\tij\exercises>java HelloWorld
So I moved back to the main directory and executed:
java org.tij.exercises.HelloWorld
and it worked, i.e.:
C:\Users\xyz\Documents\Java\javastudy\src>java org.tij.exercises.HelloWorld
Hello World!!
Since you're running it from command prompt, you need to make sure your classpath is correct. If you set it already, you need to restart your terminal to re-load your system variables.
If -classpath and -cp are not used and CLASSPATH is not set, the current directory is used (.), however when running .class files, you need to be in the folder which consist Java package name folders.
So having the .class file in ./target/classes/com/foo/app/App.class, you've the following possibilities:
java -cp target/classes com.foo.app.App
CLASSPATH=target/classes java com.foo.app.App
cd target/classes && java com.foo.app.App
You can check your classpath, by printing CLASSPATH variable:
Linux: echo $CLASSPATH
Windows: echo %CLASSPATH%
which has entries separated by :.
See also: How do I run Java .class files?
I had the same problem, mine was a little different though I did not have a package name. My problem was the Class Path for example:
C:\Java Example>java -cp . HelloWorld
The -cp option for Java and from what I can tell from my experience (not much) but I encountered the error about 20 times trying different methods and until I declared the class Path I was receiving the same error. Vishrant was correct in stating that . represents current directory.
If you need more information about the java options enter java -? or java -help I think the options are not optional.
I just did some more research I found a website that goes into detail about CLASSPATH. The CLASSPATH must be set as an environment variable; to the current directory <.>. You can set it from the command line in windows:
// Set CLASSPATH to the current directory '.'
prompt> set CLASSPATH=.
When you add a new environment setting you need to reboot before enabling the variable. But from the command prompt you can set it. It also can be set like I mentioned at the beginning. For more info, and if your using a different OS, check: Environment Variables.
One reason for this error might be
Could not find or load main class <class name>
Maybe you use your class name as different name and save the class name with another name you can save a java source file name by another name than class name. For example:
class A{
public static void main(String args[]) {
System.out.println("Hello world");
}
}
you can save as Hello.java but,
To Compile : javac Hello.java
This will auto generate A.class file at same location.
Now To Run : java A
Execute your Java program using java -d . HelloWorld command.
This command works when you have declared package.
. represent current directory/.
I had a similar problem when running java on win10
instead of
$ java ./hello
Error: Could not find or load main class ..hello
Run
$ java hello
Hello, World
I was getting the exact same error for forgetting to remove the .class extension when running the JAVA class. So instead of this:
java myClass.class
One should do this:
java myClass
I used IntelliJ to create my .jar, which included some unpacked jars from my libraries. One of these other jars had some signed stuff in the MANIFEST which prevented the .jar from being loaded. No warnings, or anything, just didn't work. Could not find or load main class
Removing the unpacked jar which contained the manifest fixed it.
I faced the same problem and tried everything mentioned here.
The thing was I didn't refresh my project in eclipse after class creation .
And once I refreshed it things worked as expected.
faced the same problem. solved by following these steps
go to directory containing the package 'org.tij.exercises' (e.g: in eclipse it may be your src folder)
use java org.tij.exercises.HelloWorld
For a lot of us, at least for me, I think the class path hierarchy is not intuitive since I'm working inside a directory structure and it feels like that ought to be it.
Java is looking at the name of the class based on it's package path, not just the file path.
It doesn't matter if:
i'm in the local directory ./packagefoo/MainClass, or
a directory up ./packagefoo/, or
one down ./packagefoo/MainClass/foo.
The command "java packagefoo.MainClass" is running off the root %CLASSPATH% which means something significant to Java. Then from there it traverses package names, not path names like us lay coders would expect.
So if my CLASSPATH is set to %CWD%/, then "java packagefoo.MainClass" will work.
If I set the CLASSPATH to %CWD%/packagefoo/ then packagefoo.MainClass can't be found.
Always "java MainClass" means nothing, if it is a member of "package", until I rip out the java code "package packagefoo;" and move the Class File up a directory.
In fact if I change "package packagefoo;" to "package foopackage;" I have to create a subfolder under CLASSPATH/foopackage or foopackage.MainClass stops working again.
To make matters worse, Between PATH, CLASSPATH, JAVAHOME, for Windows, JDeveloper, Oracle Database, and every user name it was installed under, I think a coder trying to just get something up fast ends up brute forcing path variables and structure until something works without understanding what it means.
at least i did.
Create a folder org/tij/exercises and then move HelloWorld.java file. Then run below command
javac -cp . org/tij/exercises/HelloWorld.java
AND
java -cp . org/tij/exercises/HelloWorld
I was facing similar issue but it was due to space character in my file directory where I kept my java class.
Scenario given below along with solution:
public class Sample{
public static void main(String[] args) {
System.out.println("Hello world, Java");
}
}
My Sample.java class was kept at Dir "D:\Java Programs\Sample.java"[NOTE: Package statement not present in java class].
In command prompt, changed directory to "D:\Java Programs\", my programmed compiled but failed to run with error "Could not find or load main class"
After all the possible solutions over SOF(nothing worked), I realized may b space causing me this issue.
Surprisingly removal of folder name space char['Java Programs' -> 'JavaPrograms'], my program executed successfully. Hope it helps
How do i set the classpath in a unix environment using tsch script. I try to set the path as follows but it gives me errors
setenv CLASSPATH $CLASSPATH : path but it doens't work saying -Bad : modifier in $(/). i dont understand why i cannot set this class path. Due to this i cannot run my .jar executable as i want to and i am running out of time. When i try to run the .jar file it give s me the following error
new error...it shows this when i try to run the jar file along with the path to where my jar file is actually located and this is the error i receive
Error occurred during initialization of VM
java.lang.Error: Properties init: Could not determine current working directory.
at java.lang.System.initProperties(Native Method)
at java.lang.System.initializeSystemClass(System.java:1070)
It sounds like there are at least two issues here:
1) setenv CLASSPATH $CLASSPATH : path but it doens't work saying -Bad
: modifier in $(/).
This sounds like a "tsch" error calling "setenv" with a bad value for "$CLASSPATH". Take a look at your $CLASSPATH (or post it here): the problem should be apparent.
2) Error occurred during initialization of VM
This is because you don't have a classpath yet. But fixing your "setenv()" syntax might not necessarily fix the "java init" problem - we'll just have to take it one step at a time.
Please post the value of echo $CLASSPATH, the value before you try "setenv". That should help us fix problem 1)
The classpath should be set in the manifest file inside the jar. If not, you might try unpacking the jar and running it with the java -cp *myClassPath* *myMainClass* command.
You can set the classpath with environment variables - but why bother? If you run from a script anyways, I figure specifying the -cp option is much less error-prone.