Under bug 4083527 it was decided that all file names in JAR files must be UTF-8 encoded. However, this was not documented in the specification. The java.util.jar Package Specification only refers to the Info-ZIP documentation, which does not specify the encoding of file names.

A note needs to be added to the "Info-ZIP file format" section: "In JAR files, all file names must be encoded in the UTF-8 encoding."