ant-optional-gcj software package provides Java based build tool like make - optional libraries (GCJ), 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 ant-optional-gcj
ant-optional-gcj is installed in your system.
Make ensure the ant-optional-gcj package were installed using the commands given below,
$ sudo dpkg-query -l | grep ant-optional-gcj *
You will get with ant-optional-gcj package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Java |
| Package | ant-optional-gcj |
| Version | 1.9.7-3+b1 [amd64, arm64, arme |
| Description | Java based build tool like make - optional libraries (GCJ) |
| Sub Section | Java |