I'm uploading some jars into s3 and want to set the right content-type headers for them.
I looked through what I thought was a comprehensive list, and was unable to find any mention of jar.
I found a list which might be very useful to some.
You can find a more complete (but still incomplete) list of MIME-Types here from the official Mozilla Developers Network.
For Java Archive (JAR) .jar files the correct type is indeed:
.jar | application/java-archive