ecj1 software package provides java byte code compiler used by gcj, you can install in your Ubuntu 16.10 (Yakkety Yak) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install ecj1
ecj1 is installed in your system.
Make ensure the ecj1 package were installed using the commands given below,
$ sudo dpkg-query -l | grep ecj1 *
You will get with ecj1 package name, version, architecture and description in a table
| Distro | Ubuntu 16 10 yakkety yak |
| Section | Development |
| Package | ecj1 |
| Version | 3.11.0-7 |
| Description | java byte code compiler used by gcj |
| Sub Section | Devel |