libapache-singleton-perl software package provides Singleton class for mod_perl, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libapache-singleton-perl
libapache-singleton-perl is installed in your system.
Make ensure the libapache-singleton-perl package were installed using the commands given below,
$ sudo dpkg-query -l | grep libapache-singleton-perl *
You will get with libapache-singleton-perl package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Perl |
| Package | libapache-singleton-perl |
| Version | 0.15-2 |
| Description | Singleton class for mod_perl |
| Sub Section | Perl |