JAR file format

Hi,
I need to write a C program to retrieve class files from a JAR file. Can anybody point me to any resource that explains the format of a JAR file. Basically, I need to write my own "unjar" utility. Any help would be greatly appreciated. Thanks.
CharithaT

A JAR file is simply a ZIP file. zlib will do the decompressing for you!

Similar Messages

How to install a Application in *.jar file format?

How to install a Application in *.jar file format?
I have taken the *.jar file into the device into media folder. but device is not recognizing the file format
could some one plz provide some suggestion to proceed with this?
Thanks
Mohamed Javeed

I'm having the same problem. I've put .jar into the 'system' folder but that doesn't seem to make the program work neverless see it on my device. Help.

Binary JAR file format

Hi out there,
does anybody know where I can find the specification for the binary JAR file format?
It doesn't follow the ZIP spec, there must be some additions.
Here is my problem:
I'm reading the 1. local file header, there compressed and uncompresed size is 0. Bit 3 of the
general purpose bit flag is not set so there is no Data descriptor section and there should also be no
file data section (size is 0, extra field also 0). But there are still some
bytes until the next local file header starts. What are the bytes in between??
Somewhere in the middle of the 2 local file headers is the 0x08074b50 signature, which is mentioned
in the zip spec in combination with Spanned/Split archives !??
If I'm reading a ZIP file generated with WinZip it is working fine, but when I'm reading a jar generated with
the jar tool there are this mysterious bytes, which I cannot interpret.
Thanks in advance for your help.
Cheers,
Steffen

okay, guys just in case someone is interested (doesn't seem like, but anyhow):
YES, the jar tool is not sticking exactly to the zip specification. I found out when I was
browsing through the source code of the java distribution. The local file headers are not
filled with the size information!
Quote: * We'd like to initialize the sizes from the LOC, but unfortunately
* some ZIPs, including the jar command, don't put them there.The solution for it, which I think is the standard for zip processing anyhow, is reading the
central directory of the zip file first. There you get all info including also the size, etc. of the entries
and also the offset to the local file header.
The drawback is that it's a little more complex to read a file from the end and not from the beginning
because you have to find the beginning of the central directory first, but well ...
Okay, that's it. Have fun!

Write file in jar file format

Hi all,
I have bundled my programs and xml files in the same jar. In my program, I want to update the xml files. How should I do it? I have used JarOutputStream before, but it fails...
Thanks a lot!
Best regards,
Ray

But why the API has the JarOutputStream and ZipOutputStream? Could we use these to update the files in a jar archive??
Thank a lot ^_^
Hi all,
I have bundled my programs and xml files in thesame
jar. In my program, I want to update the xml files.
How should I do it?You can't update files in a jar archive. If the XML
files are to be updated, don't put them in the jar.

How do I prevent Spotlight from categorizing 'JAR' files as 'Application'

I'm a java developer and consequently I have a lot of JAR files on the filesystem. The JAR file format is a standard archive format for java, and is used mostly to package library code - the java equivalent of a DLL. They can also be created as 'executable JAR's, but this is (very) infrequent compared to the library usage.
Spotlight seems to think every JAR file is an application, and because I have a lot of java applications and development stuff installed, I can no longer reliably use Spotlight to find actual applications because the search results are overflowing with useless JAR file entries.
Is there any way to configure spotlight to not classify JARS as applications? Or, alternately, can I make Spotlight ignore JARs completely? Either would save me a lot of time..
/Bill

There are several things in the current version of Spotlight that are either broken or just plain wrong. It looks like you have found another. When I look at the metadata for a jar file I see that its type is, well, a java jar file, and its content tree declares it to be a com.sun.java-archive. Finder gets this right: if you do GetInfo on such a jar file its kind is shown as "Java JAR file"--as it should be.
When I made a saved search, using the Kind drop-down menu to get the pre-defined Application, and then looked to see what criteria Spotlight was using to define "application" (and yes, the search included jar files in its results), I discovered Spotlight was NOT using the simple, straightforward "kMDItemKind=Application" as one would expect. Instead it is using something I had never heard of to define an Application, to wit "_kMDItemGroupId = 8"--furthermore, I believe characterizing applications that way has been deprecated. Be that as it may, it doesn't work to find the things you want, and exclude the things you don't.
There is no way for a user to fix this. The only thing you can do is not let Spotlight define the kind. Thus, if you bring up a search window do not use the Kind drop-down menu to select Application. Instead select Other from the menu and then type Application. You then get only things whose type declaration is Application, and you don't get jar files or widgets.
The other option is to exclude jar files by typing
NOT jar
in the search for box (you'll still get widgets though). You can also add that boolean restriction if you are using the menu bar Spotlight search.
Francine
Francine
Schwieder

How to use packages and jar files for applet?

Hi!
My applet takes a class say a.class.
Now this class depends on other classes that are packaged
in a directory and put separately.
I want to put this applet on the web.
So how do I manage the .class files in he package.
I have tried using jar file format.But I was not able to get it working.
Can someone please help me?
Thanks

Use Archive instead of codebase:
<APPLET CODE="MyApplet.class" ARCHIVE="MyApplet.jar" WIDTH=400 HEIGHT=300></APPLET>

Can I place jar files inside ejb-jar.jar?

Hi,
I'm reading about the packaging rules for creating an ejb-jar.jar file, and I'm wondering whether it's possible to include a jar file (containing helper classes) inside of the ejb-jar file. A "lib" dir (for containing such helper jars) doesn't seem to be part of the ejb-jar file format.
The EJB 3 spec has this to say (Ch 20, "Enterprise JavaBeans 3.0, Final Release):
"The ejb-jar file must also contain, either by inclusion or by reference, the class files for all the classes and interfaces that each enterprise bean class and the home interfaces, component interfaces, and/or web service endpoints depend on, except Java EE and J2SE classes. This includes their superclasses and superinterfaces, dependent classes, and the classes and interfaces used as method parameters, results, and exceptions"
Now, it seems that the root of the the ejb-jar file contains all the classes (in the appropriate Java package layout). But what about including JAR files? The ejb-jar spec seems to have nothing to say about a "lib" dir that can contain jars (as a WAR file can).
Summary of questions:
1) Can an ejb-jar file contain a jar file? If so, how/where?
2) Can the ejb-jar file's META-INF/MANIFEST.MF file contain a reference to a JAR file?
I'm not considering correct design at the point... I'd just like to know if these 2 scenarios are possible.
Thank you!
kamuifx

Yes, I have an ear file..................
I have an EAR file; inside the EAR I have a WAR file (web module) and an EJB-jar file (EJB module).......... the EJB need some classes placed in a jar file (a helper .jar or an util .jar)...........
my question is: How can I use the classes of the .jar files in te EJB??????
thanks

Jar-files with vm-arguments

Hi,
If I run the junit-tests in eclipse then there are no problems. When I run in jar-files format then it need the vm-arguments(Exception:Arguments not set). How can I pass arguments the my jar-files?
Thank you.

Hi everybody,
I happy, that I'm not the only one suffering from this limitation. Right now I'm writing a Java application which will be used not only by persons who have Java experience. I guess most of them wouldn't even know how else to start it than double-clicking on the jar-file. And in my opinion, that's perfectly alright! When starting an native executable, you also don't think about defining a maximum heap size and even non-developers can easily use these applications. But I don't what to start if native applications are better or not. I really love Java and I don't want to miss it, that's for sure.
But I don't understand, why on the one hand Java tries to "sell itself" as a real alternative to native applications and one the see the intention to let Java applications more and more "feel" like them (e.g. with introduction of features like TrayBar support or making it easy to open/edit/... files with any application assigned to that file type), but on the other hand there is no official way to easily setup the environment to start these Java apps. I mean, you can use Applets or the WebStart facility for deployment, but that can't be the right way! I can think about so many applications which I would really like to have as a real offline tool. What is, if the PCs I want to use my app on don't have an internet connection?
Ok, but to make a long story short, I'm really looking for any way to make it easy for the users of my application to "just use it" rather then telling them when how to increase the maximum heap size or which script they have to use to run it. And the only way I see right now is the idea of using a wrapper just for starting a new VM with additional parameters. Even this is a bad hack in my opinion, but I'll try if this is useful for me.
Anyway, I hope that maybe someone already found a better solution cause I can't believe that this problem is really uncommon.
If I find a better solution I'll let you know.
Regards,
Black Widow

Format of jar file

i need to know format of jar file, from buffer's view.
i.e. zip file is in format of structs: local_file_head, central_file_head etc (in c/c++ sense).
jar file should have similar format (a set of structs), but i can't find any info about it.
thx for any hints, links ...

>
Presumably u don't know both jar and zip file format.
Best of luck to you then, if it isn't too much trouble could you post back when you find your answer and enlighten us as to what the differences are in physical file layout between the jar file and zip file? I, for one, would be most interested in your findings. It's obvious that we won't be able to help you with this, but maybe you could help the folk who come here looking for this answer.
same? what does "same" mean?Main Entry: 1same <http://www.m-w.com/images/audio.gif>
Pronunciation: 'sAm
Function: adjective
Date: 13th century
1 a : resembling in every relevant respect b : conforming in every respect -- used with as
when i load jar file, it is totally different from zip
file in formatCare to expound on the differences? That would be most educational. Though it's odd, since, presumably you know that there are differences, and if you know what these differences are, that would be the answer to the question you originally posted.
Presumably i know zip file format.
Presumably u don't know c++ at all.
You are operating under pretty slim evidence to make such a statement, but, since it's relevance to this forum is pretty much nil, I suppose that sort of shoddy thought isn't too damaging to your central point.
Lee

Loading jar files at execution time via URLClassLoader

Hello�All,
I'm�making�a�Java�SQL�Client.�I�have�practicaly�all�basic�work�done,�now�I'm�trying�to�improve�it.
One�thing�I�want�it�to�do�is�to�allow�the�user�to�specify�new�drivers�and�to�use�them�to�make�new�connections.�To�do�this�I�have�this�class:�
public�class�DriverFinder�extends�URLClassLoader{
��private�JarFile�jarFile�=�null;
��
��private�Vector�drivers�=�new�Vector();
��
��public�DriverFinder(String�jarName)�throws�Exception{
��super(new�URL[]{�new�URL("jar",�"",�"file:"�+�new�File(jarName).getAbsolutePath()�+"!/")�},�ClassLoader.getSystemClassLoader());
��jarFile�=�new�JarFile(new�File(jarName));
��
��/*
��System.out.println("-->"�+�System.getProperty("java.class.path"));
��System.setProperty("java.class.path",�System.getProperty("java.class.path")+File.pathSeparator+jarName);
��System.out.println("-->"�+�System.getProperty("java.class.path"));
��*/
��
��Enumeration�enumeration�=�jarFile.entries();
��while(enumeration.hasMoreElements()){
��String�className�=�((ZipEntry)enumeration.nextElement()).getName();
��if(className.endsWith(".class")){
��className�=�className.substring(0,�className.length()-6);
��if(className.indexOf("Driver")!=-1)System.out.println(className);
��
��try{
��Class�classe�=�loadClass(className,�true);
��Class[]�interfaces�=�classe.getInterfaces();
��for(int�i=0;�i<interfaces.length;�i++){
��if(interfaces.getName().equals("java.sql.Driver")){
��drivers.add(classe);
��}
��}
��Class�superclasse�=�classe.getSuperclass();
��interfaces�=�superclasse.getInterfaces();
��for(int�i=0;�i<interfaces.length;�i++){
��if(interfaces[i].getName().equals("java.sql.Driver")){
��drivers.add(classe);
��}
��}
��}catch(NoClassDefFoundError�e){
��}catch(Exception�e){}
��}
��}
��}
��
��public�Enumeration�getDrivers(){
��return�drivers.elements();
��}
��
��public�String�getJarFileName(){
��return�jarFile.getName();
��}
��
��public�static�void�main(String[]�args)�throws�Exception{
��DriverFinder�df�=�new�DriverFinder("D:/Classes/db2java.zip");
��System.out.println("jar:�"�+�df.getJarFileName());
��Enumeration�enumeration�=�df.getDrivers();
��while(enumeration.hasMoreElements()){
��Class�classe�=�(Class)enumeration.nextElement();
��System.out.println(classe.getName());
��}
��}
It�loads�a�jar�and�searches�it�looking�for�drivers�(classes�implementing�directly�or�indirectly�interface�java.sql.Driver)�At�the�end�of�the�execution�I�have�found�all�drivers�in�the�jar�file.
The�main�application�loads�jar�files�from�an�XML�file�and�instantiates�one�DriverFinder�for�each�jar�file.�The�problem�is�at�execution�time,�it�finds�the�drivers�and�i�think�loads�it�by�issuing�this�statement�(Class�classe�=�loadClass(className,�true);),�but�what�i�think�is�not�what�is�happening...�the�execution�of�my�code�throws�this�exception
java.lang.ClassNotFoundException:�com.ibm.as400.access.AS400JDBCDriver
��at�java.net.URLClassLoader$1.run(URLClassLoader.java:198)
��at�java.security.AccessController.doPrivileged(Native�Method)
��at�java.net.URLClassLoader.findClass(URLClassLoader.java:186)
��at�java.lang.ClassLoader.loadClass(ClassLoader.java:299)
��at�sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:265)
��at�java.lang.ClassLoader.loadClass(ClassLoader.java:255)
��at�java.lang.ClassLoader.loadClassInternal(ClassLoader.java:315)
��at�java.lang.Class.forName0(Native�Method)
��at�java.lang.Class.forName(Class.java:140)
��at�com.marmots.database.DB.<init>(DB.java:44)
��at�com.marmots.dbreplicator.DBReplicatorConfigHelper.carregaConfiguracio(DBReplicatorConfigHelper.java:296)
��at�com.marmots.dbreplicator.DBReplicatorConfigHelper.<init>(DBReplicatorConfigHelper.java:74)
��at�com.marmots.dbreplicator.DBReplicatorAdmin.<init>(DBReplicatorAdmin.java:115)
��at�com.marmots.dbreplicator.DBReplicatorAdmin.main(DBReplicatorAdmin.java:93)
Driver�file�is�not�in�the�classpath�!!!�
I�have�tried�also�(as�you�can�see�in�comented�lines)�to�update�System�property�java.class.path�by�adding�the�path�to�the�jar�but�neither...
I'm�sure�I'm�making�a/some�mistake/s...�can�you�help�me?
Thanks�in�advice,
(if�there�is�some�incorrect�word�or�expression�excuse�me)

Sorry i have tried to format the code, but it has changed to �... sorry read this one...
Hello All,
I'm making a Java SQL Client. I have practicaly all basic work done, now I'm trying to improve it.
One thing I want it to do is to allow the user to specify new drivers and to use them to make new connections. To do this I have this class:
public class DriverFinder extends URLClassLoader{
private JarFile jarFile = null;
private Vector drivers = new Vector();
public DriverFinder(String jarName) throws Exception{
super(new URL[]{ new URL("jar", "", "file:" + new File(jarName).getAbsolutePath() +"!/") }, ClassLoader.getSystemClassLoader());
jarFile = new JarFile(new File(jarName));
System.out.println("-->" + System.getProperty("java.class.path"));
System.setProperty("java.class.path", System.getProperty("java.class.path")+File.pathSeparator+jarName);
System.out.println("-->" + System.getProperty("java.class.path"));
Enumeration enumeration = jarFile.entries();
while(enumeration.hasMoreElements()){
String className = ((ZipEntry)enumeration.nextElement()).getName();
if(className.endsWith(".class")){
className = className.substring(0, className.length()-6);
if(className.indexOf("Driver")!=-1)System.out.println(className);
try{
Class classe = loadClass(className, true);
Class[] interfaces = classe.getInterfaces();
for(int i=0; i<interfaces.length; i++){
if(interfaces.getName().equals("java.sql.Driver")){
drivers.add(classe);
Class superclasse = classe.getSuperclass();
interfaces = superclasse.getInterfaces();
for(int i=0; i<interfaces.length; i++){
if(interfaces[i].getName().equals("java.sql.Driver")){
drivers.add(classe);
}catch(NoClassDefFoundError e){
}catch(Exception e){}
public Enumeration getDrivers(){
return drivers.elements();
public String getJarFileName(){
return jarFile.getName();
public static void main(String[] args) throws Exception{
DriverFinder df = new DriverFinder("D:/Classes/db2java.zip");
System.out.println("jar: " + df.getJarFileName());
Enumeration enumeration = df.getDrivers();
while(enumeration.hasMoreElements()){
Class classe = (Class)enumeration.nextElement();
System.out.println(classe.getName());
It loads a jar and searches it looking for drivers (classes implementing directly or indirectly interface java.sql.Driver) At the end of the execution I have found all drivers in the jar file.
The main application loads jar files from an XML file and instantiates one DriverFinder for each jar file. The problem is at execution time, it finds the drivers and i think loads it by issuing this statement (Class classe = loadClass(className, true);), but what i think is not what is happening... the execution of my code throws this exception
java.lang.ClassNotFoundException: com.ibm.as400.access.AS400JDBCDriver
at java.net.URLClassLoader$1.run(URLClassLoader.java:198)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:186)
at java.lang.ClassLoader.loadClass(ClassLoader.java:299)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:265)
at java.lang.ClassLoader.loadClass(ClassLoader.java:255)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:315)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:140)
at com.marmots.database.DB.<init>(DB.java:44)
at com.marmots.dbreplicator.DBReplicatorConfigHelper.carregaConfiguracio(DBReplicatorConfigHelper.java:296)
at com.marmots.dbreplicator.DBReplicatorConfigHelper.<init>(DBReplicatorConfigHelper.java:74)
at com.marmots.dbreplicator.DBReplicatorAdmin.<init>(DBReplicatorAdmin.java:115)
at com.marmots.dbreplicator.DBReplicatorAdmin.main(DBReplicatorAdmin.java:93)
Driver file is not in the classpath !!!
I have tried also (as you can see in comented lines) to update System property java.class.path by adding the path to the jar but neither...
I'm sure I'm making a/some mistake/s... can you help me?
Thanks in advice,
(if there is some incorrect word or expression excuse me)

Adding JAR file to project

Hi All
How can i add jar to my project environment.
Actually what i did was.
Created one folder called "JavaWork" like d:\JavaWork
and put the jar file into this folder and wrote a test class which is importing some classes from the jar file.
how to use jar ? Please someone help me.
Thanks in advance
Shan

`man jar`
jar(1) jar(1)
NAME
jar - Java archive tool
SYNOPSIS
jar [ -C ] [ c ] [ f ] [ i ] [ M ] [ m ] [ O ] [ t ] [ u ]
[ v ]
[ x file ] [ manifest-file ] destination input-file
[ input-files ]
DESCRIPTION
The jar tool is a Java application that combines multiple
files into a single JAR archive file. It is also a gen-
eral-purpose archiving and compression tool, based on ZIP
and the ZLIB compression format. However, jar was
designed mainly to facilitate the packaging of Java
applets or applications into a single archive. When the
components of an applet or application (.class files,
images and sounds) are combined into a single archive,
they can be downloaded by a Java agent (like a browser) in
a single HTTP transaction, rather than require a new con-
nection for each piece. This dramatically improves down-
load time. The jar tool also compresses files, which fur-
ther improves download time. In addition, it allows indi-
vidual entries in a file to be signed by the applet author
so that their origins can be authenticated. The syntax
for the jar tool is almost identical to the syntax for the
tar(1) command. A jar archive can be used as a class path
entry, whether or not it is compressed.
The three types of input files for the jar tool are:
o Manifest file (optional)
o Destination jar file
o Files to be archived
Typical usage is:
example% jar cf myjarfile *.class
In this example, all the class files in the current direc-
tory are placed in the file named myjarfile. A manifest
file is automatically generated by the jar tool and is
always the first entry in the jar file. By default, it is
named META-INF/MANIFEST.MF. The manifest file is the
place where any meta-information about the archive is
stored. Refer to the Manifest Format in the SEE ALSO sec-
tion for details about how meta-information is stored in
the manifest file.
To use a pre-existing manifest file to create a new jar
archive, specify the old manifest file with the m option:
example% jar cmf myManifestFile myJarFile *.class
When you specify cfm instead of cmf (that is, you invert
the order of the m and f options), you need to specify the
name of the jar archive first, followed by the name of the
manifest file:
example% jar cfm myJarFile myManifestFile *.class
The manifest uses RFC822 ASCII format, so it is easy to
view and process manifest-file contents.
OPTIONS
The following options are supported:
-C Changes directories during execution of the jar com-
mand. For example:
example% jar uf foo.jar -C classes *
c Creates a new or empty archive on the standard out-
put.
f The second argument specifies a jar file to process.
In the case of creation, this refers to the name of
the jar file to be created (instead of on stdout).
For table or xtract, the second argument identifies
the jar file to be listed or extracted.
i Generates index information for the specified jar
file and its dependent jar files. For example,
example% jar i foo.jar
would generate an INDEX.LIST file in foo.jar which con-
tains location information for each package in foo.jar and
all the jar files specified in foo.jar's Class-Path
attribute.
M Does not create a manifest file for the entries.
m Includes manifest information from specified pre-
existing manifest file. Example use:
example% jar cmf myManifestFile myJarFile *.class
You can add special-purpose name-value attribute
headers to the manifest file that are not contained
in the default manifest. Examples of such headers
are those for vendor information, version informa-
tion, package sealing, and headers to make JAR-bun-
dled applications executable. See the JAR Files
trail in the Java Tutorial and the JRE Notes for
Developers web page for examples of using the m
option.
O Stores only, without using ZIP compression.
t Lists the table of contents from standard output.
u Updates an existing JAR file by adding files or
changing the manifest. For example:
example% jar uf foo.jar foo.class
adds the file foo.class to the existing JAR file
foo.jar, and
example% jar umf foo.jar
updates foo.jar's manifest with the information in
manifest.
v Generates verbose output on stderr.
x file
Extracts all files, or just the named files, from
standard input. If file is omitted, then all files
are extracted; otherwise, only the specified file or
files are extracted.
If any of the files is a directory, then that direc-
tory is processed recursively.
EXAMPLES
To add all of the files in a particular directory to an
archive:
example% ls
0.au 3.au 6.au 9.au at_work.gif
1.au 4.au 7.au Animator.class monkey.jpg
e.au 5.au 8.au Wave.class spacemusic.au
example% jar cvf bundle.jar *
adding: 0.au
adding: 1.au
adding: 2.au
adding: 3.au
adding: 4.au
adding: 5.au
adding: 6.au
adding: 7.au
adding: 8.au
adding: 9.au
adding: Animator.class
adding: Wave.class
adding: at_work.gif
adding: monkey.jpg
adding: spacemusic.au
example%
If you already have subdirectories for images, audio
files, and classes that already exist in an HTML direc-
tory, use jar to archive each directory to a single jar
file:
example% ls
audio classes images
example% jar cvf bundle.jar audio classes images
adding: audio/1.au
adding: audio/2.au
adding: audio/3.au
adding: audio/spacemusic.au
adding: classes/Animator.class
adding: classes/Wave.class
adding: images/monkey.jpg
adding: images/at_work.gif
example% ls -l
total 142
drwxr-xr-x 2 brown green 512 Aug 1 22:33 audio
-rw-r--r-- 1 brown green 68677 Aug 1 22:36 bundle.jar
drwxr-xr-x 2 brown green 512 Aug 1 22:26 classes
drwxr-xr-x 2 brown green 512 Aug 1 22:25 images
example%
To see the entry names in the jar file using the jar tool
and the t option:
example% ls
audio bundle.jar classes images
example% jar tf bundle.jar
META-INF/MANIFEST.MF
audio/1.au
audio/2.au
audio/3.au
audio/spacemusic.au
classes/Animator.class
classes/Wave.class
images/monkey.jpg
images/at_work.gif
example%
To display more information about the files in the
archive, such as their size and last modified date, use
the v option:
example% jar tvf bundle.jar
145 Thu Aug 01 22:27:00 PDT 1996 META-INF/MANIFEST.MF
946 Thu Aug 01 22:24:22 PDT 1996 audio/1.au
1039 Thu Aug 01 22:24:22 PDT 1996 audio/2.au
993 Thu Aug 01 22:24:22 PDT 1996 audio/3.au
48072 Thu Aug 01 22:24:23 PDT 1996 audio/spacemusic.au
16711 Thu Aug 01 22:25:50 PDT 1996 classes/Animator.class
3368 Thu Aug 01 22:26:02 PDT 1996 classes/Wave.class
12809 Thu Aug 01 22:24:48 PDT 1996 images/monkey.jpg
527 Thu Aug 01 22:25:20 PDT 1996 images/at_work.gif
example%
If you bundled a stock trade application (applet) into the
following jar files,
main.jar buy.jar sell.jar other.jar
and you specified the Class-Path attribute in main.jar's
manifest as
Class-Path: buy.jar sell.jar other.jar
then you can use the i option to speed up your applica-
tion's class loading time:
example$ jar i main.jar
An INDEX.LIST file is inserted in the META-INF directory
which will enable the application class loader to download
the right jar files when it is searching for classes or
resources.
SEE ALSO
keytool(1)
JAR Files @
http://java.sun.com/docs/books/tutorial/jar/
JRE Notes @
http://java.sun.com/j2se/1.3/runtime.html#exam-
ple
JAR Guide @
http://java.sun.com/j2se/1.3/docs/guide/jar/index.html
For information on related topics, use the search link @
http://java.sun.com/
13 June 2000 jar(1)

Problem while creating JAR file for my swing application

Hi...
Using my swings application I am trying to Run different software�s .
My program is Running fine from command prompt. If I create JAR file
It is giving error like �Failed to load Main-Class manifest attribute from .jar�
Can anybody help me to creating JAR file
Thanks in advance
Cheers
Mallik

hi,
User following command
jar-cmf textfile_name.txt Jarfile_name *
here you have to make manifest file
and making jar file you have reach there by command promt
and manifest file have some constraint also as well as format
format are
Manifest-Version: 1.0
Class-path: jar file name which are using in app separed by space
Created-By: 1.5.0 (Sun Microsystems Inc.)
Main-Class: Main class name
and end of file is not have carriage return

How do I add a jar file into the build path of the compiler?

Hey,
I'm trying to import a jar file into the build path of the compilation process, but it does not find the packages or the classes that are in it.
I think I don't add it right...
          ArrayList<String> options=new ArrayList<String>();
          options.add("-d");
          options.add(targetDirectory);
          options.add("-classpath");
          for(String str:includeDirectory)
               options.add(str);
          if (!compiler.getTask(writer, fileManager, diagnostics, options, classes, compilationUnits).call());
                ....and I've tried this way:
     public void setTargetDirectory(String targetDirectory) {
          this.targetDirectory = "-d " + targetDirectory;
     private void compile(Iterable<? extends JavaFileObject> compilationUnits) throws Exception {
          ArrayList<String> options = new ArrayList<String>();
          options.add(targetDirectory);
          String classPath="-cp ";// tried this also with "-classpath"
          for (String str : includeDirectory)
               classPath+=str+":";
          options.add(classPath);
     if (!compiler.getTask(writer, fileManager, diagnostics, options, classes, compilationUnits).call())
          // throw new Exception("Compilation Error");
     }Thanks in advance,
Adam.
Edited by: Adam-Z. on Feb 24, 2010 5:41 AM
Edited by: Adam-Z. on Feb 24, 2010 5:42 AM

Thank you for your reply,
Q: Are there .class files in that directory in that jar file? (the compiler doesn't ( can't )) look for directories, it can just look for specific files , and scan to get a list of all files matching certain criteria. So if there are no class files, it will say the package doesn't exist, even if there is a directory, possibly containing other files.yes there are class files in the jar, the tree structure:
j2MeDataChunkGenerator_Plugin\(lots of class files)
META-INF\manifest.mf
and thats it.
, your code will only work on windows because other platforms use a different path separator. You should use java.io.File.pathSeparator not explicit ';" when building your classpath. (this is unrelated to your problem, but you should correct it)will do, thanks.
Q: Is that error in your post formatted by your own diagnostics? (we could possibly help you better if we didn't have to guess!!)I would not post my own error code, this text is generated by the compiler diagnostic.
{code}
     System.err.println(" Error details: " + diagnostic.getMessage(null));
{code}
Q: Is line 3 of ImageCroper_Editor.java (sic) an import statement? (we could possibly help you better if we didn't have to guess!!)it is an import error... didn't the error message stated that it is an import problem? wired, I'm sure before it did. anyway it is an import error.
Also you don't show us what the variable includeDirectory is in terms of type, and contents, that might be helpful. (we could possibly help you better if we didn't have to guess!!)It has only one String object: "D:\%Important Documents\WorkSpaces\PacMan\ApplicationManager\Plug-in\Data Chunk Designer.jar"
the last file on the classpath list.
Q: Have you proven this? that i did post, in this long line of text.
Q: Is the compiler finding other classes (in other packages) in that same jar file?No. all the class files are in the jar, they all have entries that start with "j2MeDataChunkGenerator_Plugin\*.class", and since I get 47 errors I guess it does not load any other class.
thank you for you comments, the problem with having these errors, is that I can't even get a piece of information where this error is coming from, only that it is an import loading error package not found, what does that mean? that the jar was not loaded in compilation(no error about this), that the jar is corrupted(no error about this), that the path is incorrect(it is correct I made sure), that there is no such package in the jar(There is), that the compiler does not load the package(does it even do that?), really I can't even guess why this happens, I've been at this on and of all day today, really annoying.
Thanks,
Adam.

While executing a jar file I am getting an error

while exec a jar file i am getting an error
invalid file (bad magic number): Exec format error
i tried to execute it with the commnad
java -jar test.jar
or by directly too
./test.jar

Than tell me how to launch a jar file I tried different ways like
java -jar MyJar.jar
and
MyJar
and
./MyJar
but its not worked

Error While Opening an Updated JAR file

Frnds,
I have some problem with a JAR file update. Seek ur help in this regard.Here goes my problem.
I need to update a jar file ( need to replace a single .class file with a new one ). I updated the JAR file using ' jar uf ' command and it was successfull.. I removed the old JAR file and replaced it with the updated JAR file. But when i tried to invoke the JAR application using Java we start iam unable to open the applicaiton. But when i replace this upadted JAR file with the old JAR file ( using the backup) the application loads correctly.
The application is hposted in Apcahe web server. Is a server restart required after deploying the updated JAR file or is this porblem due to some other reasons.
Thanks in advance.
Regards,
Bala.

It appears that the New Report .vi only accepts the .xlt template format and not .xltx as one would commonly expect. I am currently working to determine for sure that this is the case, but it does run (mostly) properly on my end if you make that change.
When I say mostly, I mean there are a couple other minor issues with your code. First the first frame of your sequence structure is really accomplishing anything. If your intent is to open a reference to the excel template, there is no need because the New Report .vi does it automatically.
Second, you will need a file path of some sort wired in to your Save Report to File .vi or else you will get a different error message after fixing the .xlt issue. I am currently researching whether this should be marked as a required terminal instead of recommended so that it not being wired would result in a broken run arrow rather than an error.
Let me know if these suggestions resolve your issue, or if I can provide further input on what you are doing in your first frame. I will touch base again once I determine whether these are expected behaviors or bugs.
Christopher S. | Applications Engineer
Certified LabVIEW Developer
"If in doubt... flat out." - Colin McRae

JAR file format

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