java-sdk software package provides virtual package provided by gcj-6-jdk, openjdk-8-jdk, gcj-jdk, gcj-5-jdk, default-jdk, 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 java-sdk
java-sdk is installed in your system.
Make ensure the java-sdk package were installed using the commands given below,
$ sudo dpkg-query -l | grep java-sdk*
You will get with java-sdk package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Virtual packages |
| Package | java-sdk |
| Version | |
| Description | virtual package provided by gcj-6-jdk, openjdk-8-jdk, gcj-jdk, gcj-5-jdk, default-jdk |
| Sub Section | Virtual |