gcj-5-jre-lib software package provides Java runtime library for use with gcj (jar files), you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gcj-5-jre-lib
gcj-5-jre-lib is installed in your system.
Make ensure the gcj-5-jre-lib package were installed using the commands given below,
$ sudo dpkg-query -l | grep gcj-5-jre-lib *
You will get with gcj-5-jre-lib package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Java |
| Package | gcj-5-jre-lib |
| Version | 5.4.1-3 |
| Description | Java runtime library for use with gcj (jar files) |
| Sub Section | Java |