DOC: added hint; updated package version

README_SETUP.md

@@ -16,7 +16,7 @@
 ### Install the requirements on Debian
 On Debian, the required packages can be installed with:
 
-    apt-get install git make mariadb-server maven openjdk-8-jdk-headless \
+    apt-get install git make mariadb-server maven openjdk-11-jdk-headless \
       python3-pip screen libpam0g-dev unzip
 
 Note that installing MariaDB will uninstall existing MySQL packages and vice
@@ -58,8 +58,11 @@ libpam0g-dev`. Then try again.
 After a fresh clone of the repository, this is what you need to setup the
 server:
 
-1. Compile the server with `make compile`
-   1. It is recommended to run the unit tests with `make test`.
+1. Compile the server with `make compile`. This may take a while and there
+   needs to be an internet connection as packages are downloaded to be
+   integrated in the java file.
+   1. It is recommended to run the unit tests with `make test`. It may take a
+	  while.
 2. Create an SSL certificate somewhere with a `Java Key Store` file.  For
    self-signed certificates (not recommended for production use) you can do:
    - `mkdir certificates; cd certificates`