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?

Solution 1

zip -d file.jar unwanted_file.txt

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

Solution 2

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.)

Solution 3

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.

Comments

[lapo]

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

[Goaler444]

@martona I am getting the following error: zip error: Zip file structure

[yby]

@Goaler444 I had the same error, but using 7z as lapo suggested worked for me.

[Tom]

How to delete a file from a child jar or grand child jar?

[Martin Woolstenhulme]

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/

[vmishra]

Using 7z as @lapo suggested getting this error System error: E_NOTIMPL

[Alex]

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.

[Gena Batalski]

works also for *.txt and recursive (so be careful)