Create tar archive with xz compression?
Looking at the source code for the libarchive package from Apple Open Source for OS X 10.8.5, 10.9, 10.10, and macOS 10.12.3, of which contains the source code for bsdtar, it includes the ability to use xz compression directly in tar, however it was not implemented at compile time until OS X 10.9.0 and later. Although the manual page bsdtar.1 doesn't show the -J, --xz options even though it's in the bsdtar.c source code.

To create an xz compressed tar archive in OS X 10.9 or later use the following syntax examples:

tar -cJf filename.tar.xz /path/to/folder_or_file ...


Or:

tar --xz -cf filename.tar.xz /path/to/folder_or_file ...


Example:

tar -cJf Documents.tar.xz "$HOME/Documents"


Or:

tar --xz -cf Documents.tar.xz "$HOME/Documents"


I also checked the Documents.tar.xz file after it was created in a Hex Editor and it did have the proper header which included the expected 7zXZ portion of the signature.