Develop Reference

Corrupted jar file

I "converted" the jar file into a zip folder
and then to a normal folder. I opened the MANIFEST.MF file with the text editor. Then I closed it and made the folder to a jar file. When I double clicked the jar file, it says "corrupted jar file". I don't know why; is it because I opened the MANIFEST file with the text editor or why?

In the future, you can use the jar command to remove files and add them back into a jar.
List all files in the jar:
jar tvf application.jar
Extract a file from the jar:
jar xvf application.jar path/of/file/to/extract
Add a file back into the jar:
jar uvf application.jar path/of/file/to/extract
MANIFEST files get a little special handling. If you want to add it back in:
jar uvfm application.jar mymanifest
Note: In all the commands above the v flag is used to provide verbose feedback from the command and can be omitted if you want.

If I understood right, your new jar contains a redundant folder because you zipped the folder, but what you had to do is to zip only content of that folder.

Is there a possible way to copy a file to a jar file?

I would like to ask a question if there is a way to copy a file(i.e. an image) to a .jar file, because i want to deploy a program and i created folders along with the source codes(they are in the same location as the source codes) and the folders are inside the jar file (i used Netbeans to create the jar file)..... Now what i want is i would like to copy files choosen by a JFileChooser to the folders inside the jar file????
Any idea is heartily accepted..!!! Thanks in advance????
P.S.:
I already tried searching the net for answers but all they know is how to copy the file inside the jar file to another directory......

Suppose that you want to add the file images/image1.gif to the JAR file.
jar uf <fileName>.jar images/image1.gif
To change the directory use -c
jar uf <fileName>.jar -C
in this command
jar uf jar-file input-file(s)
In this command:
The u option indicates that you want to update an existing JAR file.
The f option indicates that the JAR file to update is specified on the command line.
jar-file is the existing JAR file that's to be updated.
input-file(s) is a space-delimited list of one or more files that you want to add to the Jar file.
Related Docs

A JAR file is a ZIP compressed file.
See this S.O. answer for a solutiion to add files to an exisiting ZIP archive: Appending files to a zip file with Java

How to make a jar file from code?

I have some java code written in a text file, now I want to create a jar file to use that file as a library in my android project. So what would be the best way to make a jar file from this point. Please note that I have some code written in a textfile and saved as a .txt. If I rename that file to .java and use this code
jar cf filename.jar file(s)
a jar file is created but when I decompile it in java decompiler it doesnt show the packages and that codes that's why I am unable to use it's methods. What would be the best way to do this? I need help

If you want to use the classes in your library they must be compiled and you have to manually create all the packages subfolders.
So :
1. Make a folder
2. Create each package subfolderds in it (com/foo/bar/xxx)
3. Compile each of your .java files and put them it the correct subfolders
4. Zip your folder and rename it with a .jar extension
But it is hard to do this by code, why don't create it with your IDE ?

Creating a jar File in Windows Command Prompt
Start Command Prompt.
Navigate to the folder that holds your class files:
cd \mywork
Rem -- Set path to include JDK’s bin. For example:
path c:\Program Files\Java\jdk1.5.0_09\bin;%path%
Rem -- Compile your class(es):
javac *.java
Rem -- Create a manifest file:
echo Main-Class: DanceStudio >manifest.txt
Rem -- Create a jar file:
jar cvfm DanceStudio.jar manifest.txt *.class
Rem -- Test your jar file by trying to execute it
Rem -- This will not apply for a library JAR file without any main
java -jar DanceStudio.jar

Tool for creating jar files from command line

I'm not very skilled in writing batch files and/ or java. I have a folder with several .class-Files and folders in it and I want to put them all into a executable .jar-File. I know that there is a tool called "jar - The Java Archive Tool", but that just won't work for me. My folder structure looks like this:
Folder "test"
File (a.class)
Folder "subdirectory"
File (b.class)
I want a executable .jar-File called file.jar. In this .jar should now be the file a.class and the folder subdirectory with the file b.class in it.
I don't get the .jar-Tool to run and the 7zip command line doesn't support .jars (I can't even add files to it). I want this to run from a .bat-File, so I just have to open the batch-file, it creates the .jar and puts the files in it and then closes itself again.
I hope you can help me and get what I mean.

If you have issues in executing jar command, then probably you would need to check if your path has been set correctly. You can verify if the path contains jdk location ( echo %path%) from command prompt. If not you need to update. Also you can verify using Javac -verbose command to see jdk is installed.
Once you have jdk path set, you can try below command to create jar
Jar -cf myapp.jar * --> includes all files including files from sub folders.
If you want to run from batch, you would need to mention path before jar command. Ideal place for path is to configure as environment property.

Create a text file (and call it something useful like manifest.txt). In it, put the line:
Main-Class: a
(which should be called A by convention) and include a hard return at the end.
Then create the jar with:
jar cvfm file.jar manifest.txt *.class
or
jar cvfm c:\somedir\file.jar c:\somedir\mainfest.txt *
You could just put that line in a batch file called createJar.bat and run it if you only want to create files called 'file.jar'
hth

Conversion of .class to jar and .class to exe

How do I convert:
class file to jar file using cmd?
class file to exe file?
jar file to exe?
Can I convert exe file to jar file?

Class files to jar files
Usage: jar {ctxu}[vfm0M][jar-file]
[manifest-file] [-C dir] files ...
Options:
-c create new archive
-t list table of contents for archive
-x extract named (or all) files from archive
-u update existing archive
-v generate verbose output on standard output
-f specify archive file name
-m include manifest information from specified manifest file
-0 store only; use no ZIP compression
-M do not create a manifest file for the entries
-i generate index information for the specified jar files
-C change to the specified directory and include the following
file If any file is a directory then it is processed recursively. The manifest file name and the archive file name needs to be specified in the same order the 'm' and 'f' flags are
specified.
Example 1: to archive two class files into an archive called classes.jar:
`jar cvf classes.jar Foo.class Bar.class`
Example 2: use an existing manifest file 'mymanifest' and archive
all the files in the foo/ directory into 'classes.jar':
jar cvfm classes.jar mymanifest -C foo/ .
Convert jar files to .exe file
1)JSmooth .exe wrapper
2)JarToExe 1.8
3)Executor
4)Advanced Installer
Convert .class to .exe is discussed in length here

You must have missed this. Please look into Java Archive (JAR) Files Guide.
And surely missed Real's How to for it Make a JAR executable There are multiple wrappers that do this work (converting Jar to exe, platform specific). You just need to search in StackOverflow for Jar exe

To convert (actually, package) .class files into .jar files, you use the jar tool. You can then generate a .exe file from the .jar using tools like Launch4j, JSmooth or several other packages (search the web for "jar exe").

If you are using Netbeans IDE, then creating .exe file from .class file won't take much time. In IDE, create a new project and put your java program in this project. Now follow these steps-
Right click the project and choose properties.
Choose run from left panel and enter the main class(in which main method is defined) in right panel.
Again right click the project and choose add library. Select swing layout extensions. Click add library.
4.Now select clean and build from run menu in your IDE. Make sure that you have already set your this project as main project.
Open the CMD and set the directory to your project. Go to "dist" > and type java -jar jarname.jar.
Your program is running in cmd now.
Open launch4j and provide the information required.
Run and enjoy your application.

Create jar file using command line. Answer in http://download.oracle.com/javase/tutorial/deployment/jar/build.html
Class to exe. Answer in http://www.javacoffeebreak.com/faq/faq0042.html
Jar to exe. Answer in http://viralpatel.net/blogs/2009/02/convert-jar-to-exe-executable-jar-file-to-exe-converting.html
Converting exe to a jar file is possible. But involves reverse engineering to discover what is in the exe, extract and do whatever you want with it. In my opinion, is not worth at all.