I try to create a Minecraft Plugin (it's my first one) and I can't fix this error:
So, the plugin compiles good but when the code has to execute this code :
BCrypt.checkpw(mdp, result.getString("mdp"))
that come from the lib org.mindrot.BCrypt, I have this error :
Caused by: java.lang.NoClassDefFoundError: org/mindrot/BCrypt
But, when I open my JAR with WinRAR, there is my lib bcrypt (so it's well export). And it's also in my .classpath.
Can you help me ?
Thanks.
There are several ways to configure the CLASSPATH when launching a java application via the java command. According to what you posted so far, I would use the -classpath flag:
java -classpath spigot.jar;jbcrypt.jar class.containing.main.method.MyMain
Alternatively, you could modify the MANIFEST in file spigot.jar. Refer to Adding Classes to the JAR File's Classpath.
Or you could copy jbcrypt.jar to the directory pointed to by the java System property "java.ext.dirs".
Hi Guys I have included the Webcam-Capture API in my project.
When I run it in Netbeans everything works fine. But when i compile everything to a runnable jar i get this message trying to run it by cmd line.
can anyone of you help me?
i already tried to unbound and rebound all jars and changing jdks but its not working
add -classpath flag in the command line ,pointing to the path where Webcam-Capture API exists in your file system, unless you want to create a single package executable.In your case It should be something like below
java -classpath YOURJAR.jar;folder_of_dependant_jar/*;. com.awesome.pagackage.Starter
Where YOURJAR.jar contains the com.awesome.pagackage.Starter.main(String args[])
You also mentioned that your jar is a runnable jar it also means that while exporting/building you can do one of the following way.( NOTE , this feature is in eclipse , but you would get the idea ).Each of the following options you see in the library handling does specific things.
The first option: Extracts the dependent jar into your target jar as java packaging.This means if your package is com.awesome.package and the dependent jar has package logic.package; , after the runnable jar is build you could find both these package exists in your jar file.
The second option: I think it is more on eclipse specific since eclipse adds few classes of its own , of runnable generation, so I am not explaining it here.
The third option : is the most interesting one. it creates folder stucture like below
ndon_lib\external.jar ( external jar file )
ndon.jar ( your jar file )
This time the manifest.mf file contains something like below.
Class-Path: . ndon_lib/external.jar
Main-Class: com.awesome.pagackage.Starter
You should set the classpath
java -cp "your.jar" "yourclass"
I need help including imported jar files into my java program in Linux. Here is the program:
import java.sql.*;
public class CreateCoffees
{
public static void main(String args[])
{
try {
Class.forName("com.ibm.db2.jcc.DB2Driver");
}
catch(java.lang.ClassNotFoundException e) {
System.err.print("ClassNotFoundException: ");
System.err.println(e.getMessage());
System.exit(1);
}
}
}
In order to execute Class.forName("com.ibm.db2.jcc.DB2Driver"); I need two .jar files added into the classpath:
db2jcc_license_cu.jar
db2jcc4.jar
I put these jar files into the same directory as my CreateCoffees.java file, then compile and run it like this:
javac CreateCoffees.java
java CreateCoffees
But I got this error
ClassNotFoundException: com.ibm.db2.jcc.DB2Driver
Then I tried the "-classpath" option
javac -classpath ./db2jcc_license_cu.jar:./db2jcc4.jar CreateCoffees.java
java -classpath ./db2jcc_license_cu.jar:./db2jcc4.jar CreateCoffees
but got this
Exception in thread "main" java.lang.NoClassDefFoundError: CreateCoffees
Caused by: java.lang.ClassNotFoundException: CreateCoffees
How to I include those jar files into a my runnable jar so I can run it with java -jar myjar.jar ?
Try this
java -classpath ./db2jcc_license_cu.jar:./db2jcc4.jar:. CreateCoffees
when you use -classpath it looses current directory from classpath so it needs . in classpath as well explicitly
How to include the jars of your project into your runnable jar:
I'll walk you through it step by step with Eclipse Version: 3.7.2 running on Ubuntu 12.10. I'll also show you how to make the build.xml so you can do the ant jar from command line and create your jar with other imported jars extracted into it.
Basically you ask Eclipse to construct the build.xml that imports your libraries into your jar for you.
Fire up Eclipse and make a new Java project, make a new package 'mypackage', add your main class: Runner Put this code in there.
Now include the mysql-connector-java-5.1.28-bin.jar from Oracle which enables us to write Java to connect to the MySQL database. Do this by right clicking the project -> properties -> java build path -> Add External Jar -> pick mysql-connector-java-5.1.28-bin.jar.
Run the program within eclipse, it should run, and tell you that the username/password is invalid which means Eclipse is properly configured with the jar.
In Eclipse go to File -> Export -> Java -> Runnable Jar File. You will see this dialog:
Make sure to set up the 'save as ant script' checkbox. That is what makes it so you can use the commandline to do an ant jar later.
Then go to the terminal and look at the ant script:
So you see, I ran the jar and it didn't error out because it found the included mysql-connector-java-5.1.28-bin.jar embedded inside Hello.jar.
Look inside Hello.jar: vi Hello.jar and you will see many references to com/mysql/jdbc/stuff.class
To do ant jar on the commandline to do all this automatically: Rename buildant.xml to build.xml, and change the target name from create_run_jar to jar.
Then, from within MyProject you type ant jar and boom. You've got your jar inside MyProject. And you can invoke it using java -jar Hello.jar and it all works.
In Eclipse Indigo (on Mac OSX), I have a project 'Test'. In this project I have a package 'test1'. In this package, I have a class Test.java.
In short the file structure is: Test/src/Test.java and
Test/bin/Test.class
I have a library mylib.jar in lib folder.
I also have a data file named info.dat. In info.dat, there's information about which class to load. For example, in info.dat, I specified: class=Test
then, when I run:
$ java -jar lib/mylib.jar info.dat
(NOTE: this works if I run this command in terminal and have class file in the same folder with info.dat)
the main function in mylib.jar will load Test.class.
I'm using External Tools to achieve this. Here is my External tool setup:
Location: /usr/bin/java
Working Location: /path/to/Test_folder
Argument: -cp . -jar lib/mylib.jar bin/test1/info.dat
However, when I try to run, I get this error:
LOADING INFO FROM FILE bin/test1/info.dat
=> Current directory=[not include because not important]
=> Full pathname=[not include because not important]
java.lang.ClassNotFoundException: Test
I also tried to change class=test.Test in info.dat but got a similar error
java.lang.ClassNotFoundException: test1.Test
The result shows that the info.dat was loaded ok, but the path to class file was not correct. How should I configure the external tool to do what I need? Can someone please give me some instruction?
Many thanks,
It was an easy solution with Run Configuration. I just need to pick the main class from mylib.jar in Java Application and put info.dat in the argument field.
Sorry for wasting the resource here.
I have Windows 7, installed jdk1.7.0 and its supporting jre7.
My problem is compilation part works perfectly, but while running the Java program I get this error saying:
"Could not find or load main class"
I am storing all my programs in javalab folder. I have set the path to it. Procedure looks like this:
C:\Users\user>cd\
C:\>cd javalab
C:\javalab>autoexec.bat
C:\javalab>set path=C:\Program Files\Java\jdk1.7.0\bin
C:\javalab>javac p1.java
C:\javalab>java p1
Error: Could not find or load main class p1
C:\javalab>
I was having a similar issue with my very first java program.
I was issuing this command
java HelloWorld.class
Which resulted in the same error.
Turns out you need to exclude the .class
java HelloWorld
Try:
java -cp . p1
This worked for me when I had the same problem, using Fedora (linux)
Simple way to compile and execute java file.(HelloWorld.java doesn't includes any package)
set path="C:\Program Files (x86)\Java\jdk1.7.0_45\bin"
javac "HelloWorld.java"
java -cp . HelloWorld
pause
javac should know where to search for classes. Try this:
javac -cp . p1.java
You shouldn't need to specify classpath. Are you sure the file p1.java exists?
I had almost the same problem, but with the following variation:
I've imported a ready-to-use maven project into Eclipse IDE from PC1 (project was working there perfectly) to another PC2
when was trying to run the project on PC 2 got the same error "Could not find or load main class"
I've checked PATH variable (it had many values in my case) and added JAVA_HOME variable (in my case it was JAVA_HOME = C:\Program Files\Java\jdk1.7.0_03)
After restarting Ecplise it still didn't work
I've tried to run simple HelloWorld.java on PC2 (in another project) - it worked
So I've added HelloWorld class to the imported recently project, executed it there and - huh - my main class in that project started to run normally also.
That's quite odd behavour, I cannot completely understand it.
Hope It'll help somebody. too.
i guess that you have a different class name in p1.java
Check you class name first. It should be p1 as per your batch file instruction. And then check you package of that class, if it is inside any package, specify when you run.
If package is x.y
java x.y.p1
Here is my working env path variables after much troubleshooting
CLASSPATH
.;C:\Program Files (x86)\Java\jre7\lib\ext\QTJava.zip;C:\Program Files (x86)\Java\jdk1.6.0_27\bin
PATH <---sometimes this PATH fills up with too many paths and you can't add a path(which was my case!)
bunchofpaths;C:\Program Files (x86)\Java\jdk1.6.0_27\bin
Additionally, when you try to use the cmd to execute the file...make sure your in the local directory as the file your trying to execute (which you did.)
Just a little checklist for people that have this problem still.
I've had similar problems. If you work with Eclipse, you need to go to the folder where you have your src/ folder... If you used a package - then you use
javac -cp . packageName/className
which means if you've had a package named def and main class with name TextFrame.java you'd write
javac -cp . def/TextFrame
omitting the trailing .java extension, and then you run it with the
java def/TextFrame
and if you have have arguments, then you need to supply it with arguments corresponding to your program.
I hope this helps a bit.
First, put your file *.class (e.g Hello.class) into 1 folder (e.g C:\java). Then you try command and type cd /d C:\java. Now you can type "java Hello" !
You might have the CLASSPATH environment variable already added!!
Use following to avoid further usage of -cp . in java -cp . CLASSFILE
Add . to CLASSPATH in system properties->environment variables or by cmd
set CLASSPATH=%CLASSPATH%;.;
I faced a similar problem in Eclipse. Whenever I clicked on the Run button it gave me the message, "Error: Could not find or load main class". But when I right click on the java file in the project explorer and Run As Java configuration, it works perfectly.
I think this is because it tries by default to run it in some other configuration which causes problems.
Hope this answer helps some.
If you have a single .java file to compile using command-line , then remove
topmost package parts from the code, the compile again, it will work.
This worked for me.
Sometimes what might be causing the issue has nothing to do with the main class. I had to find this out the hard way, it was a referenced library that I moved and it gave me the:
Could not find or load main class xxx Linux
I just delete that reference and added again and it worked fine again.
i had
':'
in my project name e.g 'HKUSTx:part-2'
renaming it 'HKUSTx-part-2' worked for me
You can use NetBeans IDE which is free to download and use "Open Source". You can even do other programming language in this IDE. The latest of which it supports HTML5. This makes your programming easier. If you're not familiar with it choose a book that is NetBeans integrated like Sams Teach Yourself Java in 24 Hours