I create .jar file in eclipse. I use .jar file to print text on pos printer. My program is printing correctly, but when I start .jar file is not connecting with the printer. For connecting with the printer I use javax.comm library.
Open up the jar in achiever tool edit Menifest.txt add the following
Class-Path: /path/to/requiredLibary.jar
Also See
Adding Classes to the JAR File's Classpath
Is the javax.comm jar in the classpath when you start the jar from the command line?
Something like:
java -cp myproject.jar;javax-comm-3.0.jar com.mycompany.MyMainClass
Note that the java -jar myproject.jar is incompatible with -cp, ie this doesn't work: java -cp javax-comm-3.0.jar -jar myproject.jar
Related
If I extract a Jar file into a directory, what's the correct java command to run it as if it was the jar?
Meaning, what would be the equivalent command to java -jar myProgram.jar except not using the jar itself?
I've tried stuff like java -cp ".;META-INF\lib\*" JarMain but it seems like there's still something missing there.
Do you mean that add a jar to classpath but do not run it? If so, java -cp myProgram.jar;ohterjar/libdir JarMain. If you use linux/mac,replace ; to :.
If you run jar file directly (without extracting), you can use command: java -jar jarfilename. jar
If you extract jar file into separated files, you can run .class file only. Use the command java classfilename.
You need to set path environment to java/bin directory before running above commands, or just change directory to it.
I am using getdown to create a means to update a java application.
When I have completed this tutorial, I tested if it works on command line as below:
% java -jar c:/downloads/getdown-X.Y.jar c:/netBeans/getdown/src
Thankfully, this works and launches the application. Great.
How do I make a jar file and distribute this?
I tried to make a jar file on this project but it didn't work, this project does not run. When I run this getdown-X.Y.jar on command line.
I think it still using the same file which I created before c:/netBeans/getdown/src. Eventually, it is failing to execute since it is missing the jar file. So, how to make this project into a jar file and distribute it.
I am not sure what OS you are working on.You can do this by creating an executable jar file. Please follow the steps here:
If you want to create a jar file with additional file. Here in below, if you want to create a jar file of imagine src.class with additonal text file with it which is readme.txt
c:\patel\projects\netbeans\getdown\src.class
c:\patel\projects\readme.txt
Run this command: jar -cvfm src.jar readme.txt netbeans\getdown\*.class
which is: c:\patel\projects\jar -cvfm src.jar readme.txt netbeans\getdown\*.class
Now your executable jar file is ready. To run this jar file:
run this on command prompt: java -jar src.jar
I've downloaded JAR archive from here. I want to know which class is the main. I checked Manifest file for main class specification Main-Class: com.some.className but it's not there. Where else could the main class be specified?
OkHttp is meant to be used as a library. One of the easiest ways to build java programs that need library dependencies is to use Maven. In the absence of Maven or other tools you can get the program running by copying the jar to a folder. You will also need to download okio.
To try the library out, create a java file in the same folder that contains the 2 jars and call this file GetExample.java . Paste the example source from the OkHttp site.
To compile the program, open a terminal/command prompt window and go to the location where you have GetExample.java and the jar files. Run the command:
javac -cp okhttp-2.1.0.jar GetExample.java
This should compile the file and create GetExample.class for you.
To run the program use the command:
java -cp okhttp-2.1.0.jar:okio-1.0.1.jar:. GetExample
or, if you are using windows (replace : with ;):
java -cp okhttp-2.1.0.jar;okio-1.0.1.jar;. GetExample
You should see the content of a README.md file.
I hope this helps.
I recently finished a project which works as it is supposed to in my Eclipse IDE as both multiple files and as a single file.
Eclipse exports the jar file and only makes noise about the warnings.
When I go to run the jar file with a double-click, the cursor seems to flash to a hourglass for less than a second and then nothing. When I try to run the jar file from the command line with java -jar myJarFile.jar the command prompt window seems to wait a second and then brings the file path line and cursor with no errors and no other messages.
I have double checked both my Path variable and that I have the latest version of Java installed.
Any suggestions?
Check this thread: Failing to execute the jar file using java -jar command
Basically, what you need to do is when you run the jar, you need to specify the class to be executed in the command line, like so:
java -cp test.jar com.app.ClassName
Did you just make a jar file, or a runnable jar file? If you only did the former then it will not execute on a double click. So it's Right Click the project in Eclipse -> Export -> Runnable JAR File -> Choose the appropriate Launch Configuration -> Choose where you want it to go.
Confirm that your application code is in the jar file:
jar tf myJarFile.jar
Confirm that your application's main class is listed in the Main-Class attribute in the manifest, and that any other jar files needed by your application are listed in the Class-Path attribute:
jar xf myJarFile.jar META-INF/MANIFEST.MF
cat META-INF/MANIFEST.MF
Try running with verbose logging of classes being loaded; this should show if some necessary class can't be found:
java -verbose:class -jar myJarFile.jar
I have created a JAR file in this way jar cf jar-file input-files. Now, I'm trying to run it. Running it does not work (jre command is not found):
jre -cp app.jar MainClass
This does not work either:
java -jar main.jar
(Failed to load Main-Class manifest attribute from main.jar).
I also found out that
To run an application packaged as a
JAR file (version 1.2 -- requires
Main-Class manifest header)
What is the "Main-Class manifest header"? How do I create it and where do I put it?
I'm not sure I believe your symptoms:
If the jre command isn't found, then running jre -cp app.jar should give the same error
Just adding a JAR file to the classpath shouldn't give the error you're seeing
I'd expect you to see this error if you run:
java -jar app.jar
The Main-Class header needs to be in the manifest for the JAR file - this is metadata about things like other required libraries. See the Sun documentation for how to create an appropriate manifest. Basically you need to create a text file which includes a line like this:
Main-Class: MainClass
Then run
jar cfm app.jar manifest.txt *.class
set the classpath and compile
javac -classpath "C:\Program Files\Java\jdk1.6.0_updateVersion\tools.jar" yourApp.java
create manifest.txt
Main-Class: yourApp newline
create yourApp.jar
jar cvf0m yourApp.jar manifest.txt yourApp.class
run yourApp.jar
java -jar yourApp.jar
You can run with:
java -cp .;app.jar package.MainClass
It works for me if there is no manifest in the JAR file.
I got this error, and it was because I had the arguments in the wrong order:
CORRECT
java maui.main.Examples tagging -jar maui-1.0.jar
WRONG
java -jar maui-1.0.jar maui.main.Examples tagging
The easiest way to be sure that you have created the runnable JAR file correctly, with the appropriate manifest file, is to use Eclipse to build it for you. In your Eclipse project, you basically just select File/Export from the menu, and follow the prompts.
That way, you can be sure that your JAR file is correct and will know to look elsewhere if there is still an issue. The process is described in full in FAQ How do I create an executable JAR file for a stand-alone SWT program?.
I was getting the same error when i ran:
jar cvfm test.jar Test.class Manifest.txt
What resolved it was this:
jar cvfm test.jar Manifest.txt Test.class
My manifest has the entry point as given in oracle docs (make sure there is a new line character at the end of the file):
Main-Class: Test
Try
java -cp .:mail-1.4.1.jar JavaxMailHTML
no need to have manifest file.
I discovered that I was also having this error in NetBeans.
I hope the following is helpful.
Make sure that when you go to Project Configuration you set the main class you intend for running.
Do a Build or Clean Build
Place the jar file where you wish and try: java -jar "YourProject.jar" again at the command line.
This was the problem I was getting because I had other "test" programs I was using in NetBeans and I had to make sure the Main Class under the Run portion of the Project configuration was set correctly.
many blessings,
John P
I faced the same problem. This unix command is not able to find the main class. This is because the runtime and compile time JDK versions are different. Make the jar through eclipse after changing the java compiler version. The following link helped me.
http://crunchify.com/exception-in-thread-main-java-lang-unsupportedclassversionerror-comcrunchifymain-unsupported-major-minor-version-51-0/
Try running the jar created after this step and then execute it
If your class path is fully specified in manifest,
maybe you need the last version of java runtime environment.
My problem fixed when i reinstalled the jre 8.
If you using eclipse, try below:
1. Right click on the project -> select Export
2. Select Runnable Jar file in the select an export destination
3. Enter jar's name and Select "Package required ... " (second radio button) -> Finish
Hope this helps...!