A simple shell script to grab Java spec files so you can examine and learn from them. It looks in source repositories for items with a BuildRequires on jpackage-utils. Then it grabs the location for that SRPM, downloads it, and extracts the spec file. This script is probably Fedora specific.

java-specs.sh

#! /bin/bash

packages=$(repoquery --qf "%{name}" --archlist=src --enablerepo='*-source' --whatrequires jpackage-utils | sort | uniq)
for p in $packages; do
    srpm_location=$(repoquery --qf "%{location}" --archlist=src --enablerepo='*-source' $p)
    srpm=$(curl -s -O -w '%{filename_effective}' $srpm_location)
    rpm2cpio $srpm | cpio --quiet -id ${p}.spec
    rm $srpm
done