Is there a quick way to delete a file from a Jar / war without having to extract the jar and recreate it?

Question

So I need to remove a file from a jar / war file. I was hoping there was something like "jar -d myjar.jar file_I_donot_need.txt"

But right now the only way I can see of doing this from my Linux command line (without using WinRAR/Winzip or linux equivalent) is to

Do "jar -xvf" and extract the
complete Jar file
Remove the file(s) I don't need
Rejar the jar file using "jar -cvf"

Please tell me there is a shorter way?

Since a "jar" is just a zip file, I suspect you'll have better luck on http://superuser.com. — Kirk Woll, Dec 23 '10 at 17:00
You can also try writing a shell script to wrap the whole process. Something like `./myscript.sh -d ` — Favonius, Dec 23 '10 at 17:05

score 257 · Accepted Answer · answered Dec 23 '10 at 17:11

257

zip -d file.jar unwanted_file.txt

jar is just a zip file after all. Definitely much faster than uncompressing/recompressing.

answered Dec 23 '10 at 17:11

martona

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I more often have p7zip installed instead of `zip` and in this case it's important to specify file format: `7z d -tzip file.jar dir/unwanted_file.txt` – lapo Jul 31 '13 at 10:02
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@martona I am getting the following error: zip error: Zip file structure – Goaler444 Dec 08 '13 at 12:44
@Goaler444 I had the same error, but using 7z as lapo suggested worked for me. – yby Jan 21 '14 at 22:04
How to delete a file from a child jar or grand child jar? – Tom Aug 22 '14 at 07:48
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If you want to delete a folder in the jar, make sure there is a trailing slash on the unwanted folder: `zip -d file.jar unwanted_folder/` – Martin Woolstenhulme Dec 20 '16 at 23:53
Using 7z as @lapo suggested getting this error System error: E_NOTIMPL – vmishra Dec 02 '17 at 07:40
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One more point which cost me quite some time: you can't delete a non-empty folder. One must first delete all files/folders before deleting their parent. – Alex Aug 05 '20 at 15:17
works also for *.txt and recursive (so be careful) – Gena Batalski Dec 13 '21 at 12:46

score 3 · Answer 2 · edited May 23 '17 at 11:54

3

In case you want to delete file in order to unsign signed jar, you can probably just make the .RSA file zero-sized. This can be accomplished with just jar u. See https://stackoverflow.com/a/24678645/653539 . (Worked for me, though I admit it's hack.)

edited May 23 '17 at 11:54

Community

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answered Jul 10 '14 at 14:08

Tomáš Záluský

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score 1 · Answer 3 · answered Dec 23 '10 at 17:09

In Java you can copy all the entries of a jar except the one you want to delete. i.e. you have to make a copy but don't need to create the individual files.

You can do this by

creating a new jar.
iterating though the Jar you have
copy the entry from one jar to the other, skipping any files you want.
close and replace the orginal jar if you want.

score 0 · Answer 4 · answered Dec 16 '21 at 04:30

0

If you wish to do this programatically, can use the Zip File System to treat zip/jar files as a file system. This will allow you to edit, delete, and add files to the jar file.

See Appending files to a zip file with Java

answered Dec 16 '21 at 04:30

Gamebuster19901

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score 0 · Answer 5 · answered Dec 20 '22 at 22:24

The best answer for me was in a comment by lapo on another answer on this post.

User lapo wrote:

I more often have p7zip installed instead of zip and in this case it's important to specify file format: 7z d -tzip file.jar dir/unwanted_file.txt

User lapo's comment is in response to an answer suggesting using zip -d directly since the .jar files are like .zip archives but not exactly the same format. Like others, I wasn't able to use zip -d file.jar unwanted_file.txt. That would lead to

zip error: Zip file structure invalid

But, I was able to install p7zip via brew install p7zip, and then I was able to delete using 7z d -tzip file.jar unwanted_file.txt.

Is there a quick way to delete a file from a Jar / war without having to extract the jar and recreate it?

5 Answers5

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