"Invalid or corrupt jarfile" when packaging more than 66k files

[Rogach]

I stumbled upon following problem: when packaging a project with lots of files, resulting jar file is perceived as corrupt by java runtime.

Steps to reproduce (on java 7, sbt 0.12.3):

$ # in fresh dir
$ echo "object App{}" > Main.scala
$ mkdir -p src/main/resources/
$ # the following is going to take a while :)
$ for i in {1..70000}; do touch src/main/resources/$i; done
$ sbt package
$ java -jar target/scala-2.9.2/default_*.jar
Error: Invalid or corrupt jarfile target/scala-2.9.2/default-92d531_2.9.2-0.1-SNAPSHOT.jar

The probable cause of this problem could be the 65k file limit of the old ZIP format - but java 7 already uses ZIP64 by default, and 7z reports that the resulting jar file is indeed in 64-bit format. (relevant discussion)

The same problem happens with sbt-assembly, by the way (it also uses sbt.Package).

[Rogach]

Seems that it's a problem in a way Java reads jar files on launch - and the fix will only come to us in Java 8.

Meanwhile, there is a simple workaround:

java -jar app.jar
# becomes
java -cp app.jar app.Main

• Bug in Oracle's bug db
• Discussion at SO

[harrah]

Thanks for following up on this.

[ijuma]

The bug referenced says that the "Fix version" is Java 7 update 40 (out in mid September) so looks like we'll get it sooner than Java 8.

[Rogach]

@ijuma - the resolution on that bug is "Duplicate", the actual entry about backport says "Won't Fix" (and something about that it's "too risky").

[ijuma]

You are right. My bad.