Hacker News Reader

Comment by zmmmmm | Hacker News Reader

this sounds incredibly useful but I couldn't get it to work. I just get

    java.util.zip.ZipException: invalid CEN header (bad signature)
        at java.base/java.util.zip.ZipFile$Source.zerror(ZipFile.java:1623)

if I try to do anything with a JAR file that has leading text. I'm creating it just using

   echo 'java -jar $0' | cat - test.jar > test.run.jar

Is there more to it?

View on HN

Technically, you should update the offset to the central directory in the Zip footer, along with the offsets to each file header in each central directory entry. If you don’t, the zip file reader has to apply some heuristics to locate the central directory; not all readers implement these heuristics, and those that do won’t always be robust.

The “unzip” utility can be useful as a sanity check; run “unzip -t” to test the integrity of the file.

Did you add a shebang line?

I have a small bash stub that I use. It’s roughly (I also add JAVA_OPTS, etc…):

    #!/bin/bash
    java -jar $0

Then…

    cat stub.sh myproject.jar > myexec

See: https://github.com/compgen-io/ngsutilsj/blob/master/src/scri...

https://github.com/puniverse/capsule/blob/master/capsule-uti...

This is what the (now defunkt) Capsule project prepends to get this same effect

Reply on news.ycombinator.com