Openhab @ Ubuntu 14.04 via apt not starting

Have Ubuntu 14.04 running and installed openhab2 stable via apt this morning.

When starting openhab2 via ‘service openhab2 start’ I get:
* Starting openHAB2 server openhab2
…done.

Trying to open webfrontend via ‘localhost:8080’ brings me ‘Diese Webseite ist nicht erreichbar’ (“there is no such page”)

Checking the processes:
PID BENUTZER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1114 openhab 20 0 12,871g 200004 18296 S 0,6 0,6 0:04.87 java
990 openhab 20 0 22632 3520 2984 S 0,0 0,0 0:00.00 karaf

Trying to start karaf via ‘usr/share/openhab2/runtime/client’ I get:
client: Ignoring predefined value for KARAF_HOME
Logging in as openhab
Failed to get the session.

The log files in ‘/var/log/openhab2’:
drwxr-xr-x 2 openhab openhab 4096 Feb 4 08:54 ./
drwxrwxr-x 22 root syslog 4096 Feb 4 09:16 …/
-rw-rw-r-- 1 openhab openhab 0 Feb 4 08:54 events.log
-rw-rw-r-- 1 openhab openhab 125 Feb 4 09:40 openhab.log
-rwxr-xr-x 1 openhab openhab 0 Jan 22 21:40 Readme.txt*

Content of openhab.log:
2017-02-04 09:40:14.812 [WARN ] [ache.karaf.main.ShutdownSocketThread] - Karaf shutdown socket: Invalid command '' received

The log files in ‘var/lib/openhab2/log’;
insgesamt 8
drwxr-xr-x 2 openhab openhab 4096 Feb 4 08:53 ./
drwxr-xr-x 9 openhab openhab 4096 Feb 4 08:54 …/
(i.e. there are no files)

Checked persmissions of /etc/openhab2, /var/lib/openhab2 and /usr/share/openhab2 - all are owned by user and group ‘openhab’

Starting openhab2 in debug mode (’/usr/share/openhab2/start_debug.sh’) shows following lines and then blocks bash process:
Launching the openHAB runtime…
Listening for transport dt_socket at address: 5005

Still, no luck using karaf client, web frontend, etc…

Java version is:
java version "1.8.0_101"
Java™ SE Runtime Environment (build 1.8.0_101-b13)
Java HotSpot™ 64-Bit Server VM (build 25.101-b13, mixed mode)

Thanks

Just to let you know:

installing from apt sources into a new Debian Stretch build in a VirtualBox 5.1 image with Java 8 (121) works fine - except that I do not have any home automation like Z-Wave in the VirtualBox.

Maybe there is a more profound problem with my Ubuntu.

Yet, I would be glad if openhab would write more log messages so it would be possible to trace down such situations that I experience.

Sorry, didnt’ realize you said Java was already installed.

But is that the Oracle version?

Yes, it is oracle java 8 via web8upd-repo .

What are the settings to make openhab2 more talkative, i.e. write more log messages? I also could not find any logging.properties but maybe I searched wrongly.