Converting a .class file to a .jar file

Can you please suggest as how can I convert a .class
(dot class) file into an executable .jar (dot jar)
file and how I can execute that .jar file.

use jar tool named JavaJar..
may down from http://www.pivotonic.com

Similar Messages

Beginner: Can't convert a hello.class file into a jar file: HELP PLEASE!!!

Hi, I created a hello.java file, converted into a hello.class file by using the java 2SDk compiler. The problem is that the hello.class file is in a directory I created: C:\JavaBuilder\hello.class
I have a problem converting the hello class file into a jar file. I don't know which approach to take. I've looked at tutorials...but I keep getting more confused each time I view the tutorials on creating jar files. Please can someone help..by taking me through a step by step process. Please be explicit and do not leave or assume that I know any details because I'm a new born beginner. Thank you very much, I seriously appreciate it.

Hi i did as you suggested, only with these exceptions:
jar -cvf hello.jar C:\JavaBuilder\hello.class
I did this and got the message: "adding : C:\JavaBuilder\hello.class (in=1150) (out=708) (deflated=38%)"
The problem is that when I tried to execute the jar file...by typing: " java -jar hello.jar" I received the error message: "Failed to load Main-Class Manifest attribute from hello.jar" Is there any way to correct this problem? please help, thank you.

Beginner: Can't convert a hello.class file into a jar file. Please Help!!!

Hi, I created a hello.java file, converted into a hello.class file by using the java 2SDk compiler. The problem is that the hello.class file is in a directory I created: C:\JavaBuilder\hello.class
I have a problem converting the hello class file into a jar file. I don't know which approach to take. I've looked at tutorials...but I keep getting more confused each time I view the tutorials on creating jar files. Please can someone help..by taking me through a step by step process. Please be explicit and do not leave or assume that I know any details because I'm a new born beginner. Thank you very much, I seriously appreciate it.

Hi!
first of all, you should use an upper-case character for the first letter of your classes...
To answer your question :
1) you must create a directory named "meta-inf" in your directory "C:\JavaBuilder"
2) then,you must create a file named "manifest.mf" in this directory
it's like a property file and it must contain this :
Main-Class: hello
(don't forget to type <enter> after "hello")
3) in the directory "C:\JavaBuilder", you can enter the following command :
"jar cvfM hello.jar meta-inf\manifest.mf hello.class"
(check jar.exe is in your path)
4) you can run your jar by the command :
"java -jar hello.jar"

Conversion of a .class file into a .jar file

Conversion of a .class file into a .jar file
How Will I convert a .class file into a .jar file.
Pls answer ASAP.

You don't.
You add a .class file into a .jar file. You don't convert anything.
Read the help page for jar for details.

Taglib: class not found in jar-file

I've got the following problem:
I whant to deploy a taglib to tomcat 5.0.25.
If I point to the jsp which uses the taglib I got the following error:
org.apache.jasper.JasperException: Unable to read TLD "META-INF/taglib.tld" from JAR file "file:/C:/Programme/Apache Software Foundation/Tomcat 5.0/webapps/taglibtest/WEB-INF/lib/gsa_prod3_db_taglib.jar": org.apache.jasper.JasperException: Failed to load or instantiate TagExtraInfo class: ch.gsa.prodass3.taglib.TagAddAttributeTEI
If I copy the taglib.tld out of the jar-file into WEB-INF and do the mapping in web.xml, I get this error:
org.apache.jasper.JasperException: Failed to load or instantiate TagExtraInfo class: ch.gsa.prodass3.taglib.TagAddAttributeTEI
root cause
java.lang.ClassNotFoundException: ch.gsa.prodass3.taglib.TagAddAttributeTEI
It seems like none of the files in the jar-file could be loaded.
Has anybody an idea?
Help would be very appreceated!
Greetings, Jonas

1 - double check the class is in the jar file, in that path, and is spelt correctly
2 - restart Tomcat
3 - check the contents of the tld file - particularly the extra-info tag and class name for it.

How can I access my java class file in a .jar file ...PLz Help anyone!!

Hi Folks,
I am new in Java programming, have a .jar file that contains .java files that I want no access and use from another .java file. These files in the .jar file basically form a library thus have no main-method. However I can not declare an instance of the library (in the .jar file) and use it within my program.
Plz help ...I have tried all I know in vain.
Thanks.

temba wrote:
Hi Folks,
I am new in Java programming, have a .jar file that contains .java files that I want no access and use from another .java file. These files in the .jar file basically form a library thus have no main-method. However I can not declare an instance of the library (in the .jar file) and use it within my program. You are making little sense. You can't instantiate .java files.
Plz help ...I have tried all I know in vain.
Thanks.Could you post WHAT you have tried and also post what error messages you received?

Can Netbeans put a jar file In a jar file?

I just went through the process of getting Eclipse to create a jar file that would execute from a command prompt using a plugin called fatjar :
http://fjep.sourceforge.net/
Details from other thread :http://forum.java.sun.com/thread.jspa?threadID=5219638&tstart=0
I really would like to use netbeans but i now have the exact same problem trying to make a jar file in netbeans 5.5.1
I am using a package from icaste.com It has a
.dll file to put in the windows directory
JCommSerial_3_0.jar file that contains all the classes
I can compile and run a file in the IDE and it works fine
The Jar file does not contain the classes so i get errors when running from command line.
Here is the layout of my screen and result of run command in IDE
http://www.acousticlights.com/netbeans.png
What do I need to try?

georgemc wrote:
Why is everyone so obsessed with doing this? The gains are minimal and the problems numerousBecause we are new and don't understand how the java VM actually runs code and the error messages sent by the java machine are cryptic.
My first attempt at using an external jar in a java program lead me to believe that all of the code for a java program would be in a jar file including external jar files, after all the JDK standard library has tons of jars in it so I assumed the external jar file would be linked (as most other programming compiler/linkers I have worked with in my top down programming life).
I find out the answer is so simple that the external jar file could not be found by the VM running my jar file. Like I said, if the VM would have just gave me an error that it could not find a file on a specific directory i never would have perused the idea of jar in a jar (fatjar plugin for Eclipse for example)
Really this is like getting into a race car and not knowing at what RPM to shift gears, sure you can press the pedal and make it go but if you don't understand how it works under the hood you are going to blow the engine if you keep it in first gear.
I have read many posts on these errors, the reason is the error message is just not very descriptive of the original problem. If I try and open a database called xyz.dbf that has one field defined as lastname, in C for example, I would not give the error message "Lastname could not be found) when indeed the lastname could not be found but the reason it could not be found was because the database xyz.dbf could not be found. Further , adding to the error message that the system is looking for xyz.dbf on drive X- subdirectory -mydatabases would complete the error message and allow the user to fix the error. Just what is a non java programmer that is using my java program suppose to do with an Ecception Error in (main) bla bla bla... I know now I need to check for library files myself within my own java programs and give a better error message to the user before the java VM sends out it's cryptic message.
Edited by: metron9 on Sep 25, 2007 11:00 AM

Reading an xml file from a jar file

Short question:
Is it possible to read an xml file from a jar file when the dtd is
placed inside the jar file? I am using jdom (SAXBuilder) and the default
sax parser which comes with it.
Long Question:
I am trying to create an enterprise archive file on Weblogic 6.1. We
have a framework that is similar to the struts framework which uses it's
own configuration files
I could place the dtd files outside the jar ear file and specify the
absolute path in an environment variable in web.xml which is
configurable through the admin console.
But I want to avoid this step and specify a relative path within the jar
file.
I have tried to use a class which implements the entityresolver as well
as try to extend the saxparser and set the entity resolver within this
class explicitly, but I always seem to sun into problems like:
The setEntityresolver method does not get called or there is a
classloader problem. i.e. JDOM complains that it cannot load My custom
parser which is part of the application
Vijay

Please contact the main BEA Support team [email protected]
They will need to check with product support to determine
the interoperatablity of Weblogic Server with these other
products.

Problem in include library files into my jar file

i am new to this jar archiving...I have created a GUI with java swings..and i also use mysql driver to connect my database now i want to make an executable jar file for my GUI..with coonector i have done the following
I have compiled my program and placed all the .java and .class files in
c:\ java\ bin\ jarexample
next i created a manifest file called mainClass.txt which contains
Main-Class: AppletMain (where AppletMain is my mainclass).. I placed this txt file also in c:\ java\ bin\ jarexample
i m also set Class-path in manifest file Class-Path: mysql-connector-java-3.1.10-bin.jar
next i ran jar cmf mainClass.txt example.jar *.class mysql-connector-java-3.1.10-bin
With this line, I told jar to create a JAR file (option c) with modifications to the manifest file (option m) as specified within mainClass.txt, naming the JAR file (option f) as example.jar and including everything that matches the pattern *Class and mysql connector
now my problem is ...my MYSQL connection need some Library files from a package called org and class Driver.class to generate connection I include this library files also in my example.jar....
But when i execute this jar file using :java -jar example.jar
this is executed BCOZ tha example.jar file use mysql-connector-java-3.1.10-bin.jar file from system.
If i m this mysql-connector-java-3.1.10-bin.jar file from system from system then it is not run.
Can anyone please tell me how can i include this library file to my jar file( ie example.jar)
Thankyou

Double post. Please post replies on the other thread.
http://forum.java.sun.com/thread.jspa?threadID=656781&tstart=0

Java Files inside the jar file cannot be read or accessed through Eclpse

The Java File inside the jar file of the eclipse cannot be accessed through the Eclipse . It shows error for the modules in the jar file .
But when compiled with adding the jar files to the class path the compilation is successful .
How can i browse through the files in the jar like going into the function definition .
TIA ,
Imran

Open MPlayer OSX and show the playlist (command-shift-p) then drag the file into the playlist. Click the file in the playlist and click the "i"nfo button. What does it list for file, video and audio format?
Not all of the codecs used in avi and wmv files are available for OS X so I'm guessing your file happens to be using one that isn't...

Problem loading image from jar file referenced by jar file

First, I searched this one and no, I didn't find an answer. Loading images from jar files has been pretty much done to death but my problem is different. Please read on.
I have my application, a straight up executable running from Eclipse. It uses a jar file, call it JarA. JarA launches a GUI that is located in another jar file. Call it JarB. To recap:
My application calls JarA -> JarA loads classes from JarB -> JarB looks for images to place in a GUI it wants to show on the screen
When JarB goes to load an image the following happens:
java.lang.NullPointerException
     at sun.misc.URLClassPath$3.run(URLClassPath.java:316)
     at java.security.AccessController.doPrivileged(Native Method)
     at sun.misc.URLClassPath.getLoader(URLClassPath.java:313)
     at sun.misc.URLClassPath.getLoader(URLClassPath.java:290)
     at sun.misc.URLClassPath.findResource(URLClassPath.java:141)
     at java.net.URLClassLoader$2.run(URLClassLoader.java:362)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.net.URLClassLoader.findResource(URLClassLoader.java:359)
     at java.lang.ClassLoader.getResource(ClassLoader.java:977)
     at org.cubrc.gmshell.gui.MainWin.preInit(MainWin.java:152)
     at org.cubrc.gmshell.gui.MainWin.<init>(MainWin.java:135)
The code from JarB that loads the image looks like this:
          URL[] oSearch = {Main.class.getResource("images/")};
          URLClassLoader oLoader = new URLClassLoader(oSearch);
          imgIcon = new ImageIcon(oLoader.getResource("icon.gif"));
          imgMatchRunning = new ImageIcon(oLoader.getResource("gears.gif"));
          imgMatchStill = new ImageIcon(oLoader.getResource("gears-still.gif"));
          imgMagnify = new ImageIcon(oLoader.getResource("magnify.gif"));This looks right to me and JarB certainly has an images directory with those files. But I'm in hell right now because I don't know where to place the images to make this work or if you can even attempt to load images with a dependency chain like this.
Any help very appreciated!

Have you tried to move your image-files out of the jar file and place them in the sam folder as the jar-file? I think that would help.
When you try to load the image-file you get the NullPointerException because the program tries to read a file it can't find. Remember that a jar file IS a file and not a directory.
If you want to read somthing inside the jar-file you need to encode it first.
Have you tried to read the jar-file with winRar. It makes it easy to add and remove files in your jar-file.

How to read a file inside the JAR file

Hi All,
I want to save some preferences in a file called "preferences". I kept the preferences file under my java package.
If i am running the code inside the NetBeans 6.9 IDE it's working file. But once i have created a JAR and try to run the application, it couldn't find the path.
Please help me that how to resolve this issue. I don't want to save this preferences file outside of my JAR (i.e) within my java package.
Here is the code,
package mypackage;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
public class ReadFile
    private void writeFile()
        try
            OutputStream out = new FileOutputStream(getClass().getClassLoader().getResource("mypackage/preferences").getPath().replace("%20", " "));
            PrintWriter writer = new PrintWriter(out);
            writer.println("Hello Java!");
            writer.close();
            out.close();
        catch (Exception ex)
            System.out.println(ex.getMessage());
    private void readFile()
        try
            FileInputStream fi = new FileInputStream(getClass().getClassLoader().getResource("mypackage/preferences").getPath().replace("%20", " "));
            BufferedReader br = new BufferedReader(new InputStreamReader(fi));
            System.out.println(br.readLine().trim());
            br.close();
            fi.close();
        catch (Exception ex)
            System.out.println(ex.getMessage());
    public static void main(String[] args)
        ReadFile read = new ReadFile();
        read.writeFile();
        read.readFile();
}If i run the JAR, i get the following error message,
{color:#ff0000}*file:\my jar path\jarname.jar!\mypackage\preferences (The filename, directoryname, or volume label syntax is incorrect)*{color}

Thanks sabre150,
sabre150 wrote:
You cannot update a running jar file. I am sorry. I didn't know about it. Thanks to point out.
There are two ways I approach this depending on my exact requirements -
1) use the java.util.prefs.Preferences APII will try this one
>
2) if not already present I copy the preferences file from the jar to a known place. I use a directory in the user's home directory and normally make the directory name the program with a '.' prefix.
One cannot access files in a jar file using the File API. One needs to use the getResource() or getResourceAsStream() methods on Class or ClassLoader.

How to read, write file inside the JAR file?

Hi all,
I want to read the file inside the jar file, use following method:
File file = new File("filename");
It works if not in JAR file, but it doesn't work if it's in a JAR file.
I found someone had the same problem, but no reply.
http://forum.java.sun.com/thread.jsp?forum=22&thread=180618
Can you help me ? I have tried this for all night !
Thanks in advance
Leo

If you want to read a file from the JAR file that the
application is packaged in (rather than a separate
external JAR file) you do it like this ...
InputStream is =
ClassLoader.getSystemResourceAsStream("filename");Better to use
this.getClass().getClassLoader().getResourceAsStream();
From a class near to where the data is. This deals with multiple classloaders properly.

Problem opening a zip file within a jar file

Hi,
I have a jar file in a tomcat web server. The jar file includes a zip file which I've been trying to open with the following sentences:
SpellDictionary dict = null;
File f = new File(getClass().getResource*("us_US.zip"*).getFile());
dict = new OpenOfficeSpellDictionary( new ZipFile( f ) );
I'm getting this exception:
2007-09-13 15:31:38 java.util.zip.ZipException: No such file or directory
at java.util.zip.ZipFile.open(Native Method)
at java.util.zip.ZipFile.<init>(ZipFile.java:203)
at java.util.zip.ZipFile.<init>(ZipFile.java:84)
at com.iir.newsAdministration.textEditor.TextEditorSpellChecker.<init>(TextEditorSpellChecker.java:62)
If I run the application with the builded classes instead of the jar file, it works fine.
Any ideas about how can I make it work with the jar file?
Thanks in advance
Natalie

File f = new File(getClass().getResource*("us_US.zip"*).getFile());
This is not going to work.
What you need to do is create a Jar/ZipFile from your jar, then extract the ZipFile, put that in a temporary location, then open that with another ZipFile object

Adding Jar files in another Jar file

Hi,
I have a very bad problem. Please some one help me here.
I created a Java application which is organized in a package structure.
The directories and files in the JAr files are following
1) TestApplication.class - The application startup class.
2) com(dir) - The start of my package structure, all the othere files are in this directory
3) config (dir) - Directory containing all the configuration files.
4) hsqlDatabase (dir) - contains the inprocess database
5) images (dir) - Contains all the images used in the application.
6) lib (dir) - Contains all the other jar files that i use in this application, i have about 10 of them in this directory.
I created a jar file which contains all these dir and the TestApplication.class file. I also uses the 'Main-Class' and 'Class-Path' attribute.
This is my META-INF\MANIFEST.MF file
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.6.1
Created-By: 1.4.2_03-b02 (Sun Microsystems Inc.)
Built-By: jj
Main-Class: TestApplication
Class-Path: .;./lib/commons-codec-1.3.jar;./lib/commons-httpclient-3.0
-alpha1.jar;./lib/hsqldb.jar;./lib/kunststoff-2_0_1.jar;./lib/kunstst
off.jar;./lib/liquidlnf.jar;./lib/log4j-1.2.8.jar;./lib/looks-1.2.2.j
ar;./lib/jcalendar.jar;./lib/mysql-connector-java-3.0.9-stable-bin.ja
r;./lib/ViolinStrings.jar;./config;./hsqlDatabase;./images
When i try to run the application through
java -jar xxxxx.jar
1) the first problem is that it starts the application (TestApplication.class) and also loads the rest of the application in my package(com\...). But it cannot find the classes which are in the jar file (in the lib dir).
2) I am also trying to read from a config\xxxxx.properties file, but i get an exception showing FileNotFound (xxxxx.properties).
Hope that this will help you to help with my problem,
Thanks in advance,
Jobby

1) the first problem is that it starts the
application (TestApplication.class) and also loads
the rest of the application in my package(com\...).
But it cannot find the classes which are in the jar
file (in the lib dir).
jars inside of jars do not work like you want them too. You should be able to write a class loader that can find those other jars, but Java does not directly support jars inside of jars. Of course, you can unjar the other jars and use them as well.
2) I am also trying to read from a
config\xxxxx.properties file, but i get an exception
showing FileNotFound (xxxxx.properties).
Is this file also in the jar? If it is, you need to use getClass().getResource() to find the file.

Updating a properies file in a .jar file

Hi
I have an application that reads a properties file from a .jar file using the getSystemResourceAsStream method on the ClassLoader class. What I would like to be able to do is to change values in this properties file when the application exits so the next time into the application the last used values for certain text boxes are remembered from last time. Can anyone suggest a way to achieve this. I can write the properties file out using the FileWriter class and this works but I read it is not a good idea to use these classes for this purpose.
Thanks in advance

Those .properties files can perfectly be writting using a FileOutputStream
(not a Writer). Updating a .properties file in a .jar file isn't possible
without rewriting the entire .jar file.
Your scenario should work fine: if the .properties file doesn't exist, get
a "prototype" from the .jar file and store it as an independent file. Update
this file using a FileOutputStream ad lib.
kind regards,
Jos
ps. if you don't like this scenario, you could have a look at the Preferences class.

Converting a .class file to a .jar file

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