[java] Extracting .jar file with command line

I am trying to extract the files from a .jar file. How do I do that using command line?

I am running Windows 7

To extract the jar into specified folder use this command via command prompt

C:\Java> jar xf myFile.jar -C "C:\tempfolder"

jar xf myFile.jar
change myFile to name of your file
this will save the contents in the current folder of .jar file
that should do :)

Note that a jar file is a Zip file, and any Zip tool (such as 7-Zip) can look inside the jar.

Given a file named Me.Jar:

1. Go to cmd
2. Hit Enter

3. Use the Java jar command -- I am using jdk1.8.0_31 so I would type

   C:\Program Files (x86)\Java\jdk1.8.0_31\bin\jar xf me.jar

That should extract the file to the folder bin. Look for the file .class in my case my Me.jar contains a Valentine.class

Type java Valentine and press Enter and your message file will be opened.

You can use the following command: jar xf rt.jar

Where X stands for extraction and the f would be any options that indicate that the JAR file from which files are to be extracted is specified on the command line, rather than through stdin.

In Ubuntu:

unzip file.jar -d dir_name_where_extracting

Java has a class specifically for zip files and one even more specifically for Jar Files.

java.util.jar.JarOutputStream
java.util.jar.JarInputStream

using those you could, on a command from the console, using a scanner set to system.in

Scanner console = new Scanner(System.in);
String input = console.nextLine();

then get all the components and write them as a file.

JarEntry JE = null;
while((JE = getNextJarEntry()) != null)
{
    //do stuff with JE
}

You can also use java.util.zip.ZipInputStream instead, as seeing a JAR file is in the same format as a ZIP file, ZipInputStream will be able to handle the Jar file, in fact JarInputStream actually extends ZipInputStream.

an alternative is also instead of getNextJarEntry, to use getNextEntry