Creating a JAR File: 10 Steps (with Pictures)

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Creating a JAR File: 10 Steps (with Pictures)
Creating a JAR File: 10 Steps (with Pictures)

The JAR file format is a compressed format and is mainly used to distribute Java applications and libraries. It is based on the ZIP file format, and functions in the same way. Many files are compressed and packed together into a single file, making it easier to send over a network. If you need to package a Java application or library, you can create a JAR file using the Java Development Kit (JDK) and your computer's command prompt.


Method 1 of 2: Windows

Create JAR File Step 1

Step 1. Prepare your files

Place all the files you want to include in the JAR in one folder. You're going to reference it from a single command line, so it's not convenient to have to specify multiple paths.

Create JAR File Step 2

Step #2. Open Command Prompt

You can do this via Start and after that To carry out.

Type "cmd" in the text field and click "OK".

Create JAR File Step 3

Step 3. Navigate to the folder where your files are stored

By default, the command prompt looks like this: "C:\>."

  • To view other directories, use the "change directory" command by typing "cd".
  • For example, if your files are stored in "C:\myfiles," you would type "cd \myfiles."
  • If you want to go directly to the correct directory, hold down Shift and right-click on the folder in the Explorer. Then select "Open command window here".
Create JAR File Step 4

Step 4. Set the path to the directory of the JDK bin

You will need to run the jar.exe utility to create a JAR file, and that file is in the bin directory.

  • Use the "path" command to specify the JDK bin directory. For example, if you installed JDK in the default location, you would type: "path c:\Program file\Java\jdk1.5.0_09\bin"
  • If you're not sure what the exact directory is, navigate to it in Windows Explorer and make a note of the full path to the directory.
Create JAR File Step 5

Step 5. Create the JAR file

The command line for creating the JAR file looks like this: "jar cf 'jar-file'.jar input-file(s)."

  • The "jar" part refers to the jar.exe program, which compiles the JAR file.
  • The "c" option indicates that you want to create a JAR file.
  • The "f" option means you want to specify a file name.
  • The "jar-file" part is where you type the name of the file.
  • "Input-file(s)" is a space-separated list of all files to be added to the JAR file.
  • For example, you could type: "jar cf myjar manifest.txt myclass.class." This will create a JAR file with the file name "myjar.jar" that also contains the files "manifest.txt" and "myclass.class".
  • If you add directories to the JAR file, the jar.exe utility will automatically add the contents.

Method 2 of 2: Mac

Create JAR File Step 6

Step 1. Prepare your files

Place all the files you want to include in the JAR in one folder.

Open a Terminal command prompt, and set it to the target directory where the JAR files are located

Create JAR File Step 7

Step 2. Compile class

For example, compile with:

  • javac
  • This produces a.class file, needed for the JAR file.
Create JAR File Step 8

Step 3. Create a manifest file

Save it with the extension.txt using the text editor and enter:

  • Main-Class: HelloWorld (or whatever your filename is)
  • Note: This manifest file must end with a newline character.
Create JAR File Step 9

Step 4. Create the JAR file with the following code:

jar cfm Manifest.txt HelloWorld.jar HelloWorld.class

Create JAR File Step 10

Step 5. Run the file:java -cp filename.jar mainclass


  • You can digitally sign JAR files to make them more secure. You can do this with the "jarsigner" command in the JDK.
  • You can also create JAR files using standard compression tools, such as those for creating ZIP files. Be careful that you indicate that the manifest file is the first file in the archive.

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