JAR - extracting specific files

Question

I have .class and .java files in JAR archive. Is there any way to extract only .java files from it? I've tried this command but it doesn't work:

jar xf jar-file.jar *.java

Why don't you just extract all the files and delete the ones you don't need? — Strikeskids, Sep 22 '14 at 11:24
Where does this JAR come from? It's not a good practice to package the source and the class files in the same JAR... — Puce, Sep 22 '14 at 11:27
Because it's uglier and slower solution. There's about 10000 files there. — user3521479, Sep 22 '14 at 11:30

score 49 · Answer 1 · edited Jun 20 '20 at 09:12

From the source:

To extract only certain files from a jar file, supply their filenames:

C:\Java> jar xf myFile.jar foo bar

Using wildcards is a shell thing, and you should not expect it to work when extracting from a JAR file (which, as you've realized, is the case).

What you can do, is supply a list of the files you want to extract, via the @ modifier:

jar xf my.jar @myfiles.lst

where myfiles.lst would be:

com/my/MyClass.java
com/my/MySecondClass.java

This file could easily be created automatically with creative use of jar tvf, awk and your desired extraction pattern. I'll leave that as an exercise and/or another SO question :-)

Or you could use unzip - a JAR file is basically a zip-file.

Cheers,

Ok I know it, this is in documentation, but does jar support any regexes? I've not found it anywhere:/ — user3521479, Sep 22 '14 at 11:40

score 41 · Accepted Answer · answered Sep 22 '14 at 11:42

41

You can use the unzip command which accepts wildcards in its arguments (which is not the case of the jar command). Something like this should do the trick ( disclaimer : not tested)

unzip youFile.jar "*.java"

answered Sep 22 '14 at 11:42

Pierre Rust

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score -6 · Answer 3 · answered Apr 22 '15 at 10:29

-6

There shouldn't be any *.java files in a jar, only class files. You can check the content of the jar first by running:

jar tvf jar-file.jar

answered Apr 22 '15 at 10:29

Adrian Ng

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It's not uncommon practice to publish source jars. – Noel Yap Aug 30 '19 at 00:24
Excuse me but how is this an answer ? – alegria Oct 20 '22 at 06:40

JAR - extracting specific files

3 Answers3