May 24, 2019

Oracle JDeveloper: Is this IDE dead? Are there new releases?

Some weeks ago i read the Java Magazine (

They report from a survay taken place in 2018 about Java. One of the questions was which application server do you use in production:

This was not really amazing.
But the question about the IDE gave a really surprising result:

More developers use IntelliJ than Eclipse?
Not really surprising was the usage of Oracle's JDeveloper: Only 1% of the developers use this tool.

You have to keep in mind, that with using Oracle's SOA Suite / BPEL / ESB you are forced to use JDeveloper - which means this SOA stuff is not used by many people out there.

If you take a look on the Oracle homepage you will find:

The last version was released in august 2017 - this does look like living software.

For architects and consultants JDeveloper can be very useful because it has a very nice visualization of XSDs and XSLTs (Take a look here). So hopefully JDeveloper will stay alive...

May 10, 2019

Wireguard: Status information / using the wg command

After the installation of wireguard on two servers i shut down the secondary server and after 4h i did the wg command:
root@zerberus:~# wg
interface: wg0
  public key: XXX=
  private key: (hidden)
  listening port: 46932

peer: YYY=
  allowed ips:
  latest handshake: 4 hours, 19 minutes, 2 seconds ago
  transfer: 348 B received, 436 B sent
With the "ip addr" command there is nothing really interesting:
root@zerberus:~# ip addr show wg0
5: wg0:  mtu 1420 qdisc noqueue state UNKNOWN group default qlen 1000
    inet scope global wg0
       valid_lft forever preferred_lft forever
Just to get some information about the "wg" command:
root@zerberus:~# wg help
Usage: wg  []

Available subcommands:
  show: Shows the current configuration and device information
  showconf: Shows the current configuration of a given WireGuard interface, for use with `setconf'
  set: Change the current configuration, add peers, remove peers, or change peers
  setconf: Applies a configuration file to a WireGuard interface
  addconf: Appends a configuration file to a WireGuard interface
  genkey: Generates a new private key and writes it to stdout
  genpsk: Generates a new preshared key and writes it to stdout
  pubkey: Reads a private key from stdin and writes a public key to stdout
You may pass `--help' to any of these subcommands to view usage.
and one more example:
root@zerberus:~# wg showconf wg0

ListenPort = 46932
PrivateKey = TTT=

PublicKey = XXX=
AllowedIPs =
Endpoint =

May 4, 2019

firefox extension do not work anymore....

Today some of my extensions stopped to work and a reinstall failed due to "Download failed. Please check your connection.":

There is an article about this issue, which says, that this is due to an expired certificate:

The workarounds stated there, do not work for my extensions, so i have to wait, that firefox gets a solution (and a new certificate).

For all others with this problem: Do not deinstall your extensions (like i did) - just wait...

Edit: Here the statement from mozilla:
On twitter i found this nice comment

Edit: For latest infos read

May 3, 2019

Wireguard: Installation & configuration

To install wireguard i followed this instruction.
First step is to add the repository to your machine:

root@zerberus:~# add-apt-repository ppa:wireguard/wireguard
 WireGuard is a novel VPN that runs inside the Linux Kernel. This is the Ubuntu packaging for WireGuard. More info may be found at its website, listed below.

More info:
Packages: wireguard wireguard-tools wireguard-dkms

Install with: $ apt install wireguard

For help, please contact 
Then the installion:

root@zerberus:~# apt install wireguard
Paketlisten werden gelesen... Fertig
Abhängigkeitsbaum wird aufgebaut.       
Statusinformationen werden eingelesen.... Fertig
Die folgenden Pakete wurden automatisch installiert und werden nicht mehr benötigt:
  btrfs-tools geoip-database-extra libcryptui0a libjs-openlayers seahorse-daemon
Verwenden Sie »apt autoremove«, um sie zu entfernen.
Die folgenden zusätzlichen Pakete werden installiert:
  wireguard-dkms wireguard-tools
Die folgenden NEUEN Pakete werden installiert:
  wireguard wireguard-dkms wireguard-tools
0 aktualisiert, 3 neu installiert, 0 zu entfernen und 1 nicht aktualisiert.
Es müssen 640 kB an Archiven heruntergeladen werden.
Nach dieser Operation werden 4.814 kB Plattenplatz zusätzlich benutzt.
Möchten Sie fortfahren? [J/n] 
Holen:1 bionic/main amd64 wireguard-dkms all 0.0.20190123-wg1~bionic [551 kB]
Holen:2 bionic/main amd64 wireguard-tools amd64 0.0.20190123-wg1~bionic [85,2 kB]
Holen:3 bionic/main amd64 wireguard all 0.0.20190123-wg1~bionic [4.136 B]
Es wurden 640 kB in 0 s geholt (1.307 kB/s).
Vormals nicht ausgewähltes Paket wireguard-dkms wird gewählt.
(Lese Datenbank ... 471444 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von .../wireguard-dkms_0.0.20190123-wg1~bionic_all.deb ...
Entpacken von wireguard-dkms (0.0.20190123-wg1~bionic) ...
Vormals nicht ausgewähltes Paket wireguard-tools wird gewählt.
Vorbereitung zum Entpacken von .../wireguard-tools_0.0.20190123-wg1~bionic_amd64.deb ...
Entpacken von wireguard-tools (0.0.20190123-wg1~bionic) ...
Vormals nicht ausgewähltes Paket wireguard wird gewählt.
Vorbereitung zum Entpacken von .../wireguard_0.0.20190123-wg1~bionic_all.deb ...
Entpacken von wireguard (0.0.20190123-wg1~bionic) ...
wireguard-dkms (0.0.20190123-wg1~bionic) wird eingerichtet ...
Loading new wireguard-0.0.20190123 DKMS files...
Building for 4.17.0-rc3
Building initial module for 4.17.0-rc3
Secure Boot not enabled on this system.

Running module version sanity check.
 - Original module
   - No original module exists within this kernel
 - Installation
   - Installing to /lib/modules/4.17.0-rc3/updates/dkms/


DKMS: install completed.
wireguard-tools (0.0.20190123-wg1~bionic) wird eingerichtet ...
wireguard (0.0.20190123-wg1~bionic) wird eingerichtet ...
Trigger für man-db (2.8.3-2ubuntu0.1) werden verarbeitet ...
And then the configuration:
(i extracted the steps from the video here)
root@zerberus:~# wg genkey > /root/private.wireguard
Warning: writing to world accessible file.
Consider setting the umask to 077 and trying again.

root@zerberus:~# ls -l /root/
insgesamt 4
-rw-r--r-- 1 root root 45 Apr 27 18:55 private.wireguard

root@zerberus:~# cat /root/private.wireguard 
root@zerberus:~# wg pubkey  < /root/private.wireguard

root@zerberus:~# ip link add wg0 type wireguard
root@zerberus:~# ip addr add dev wg0
root@zerberus:~# wg set wg0 private-key /root/private.wireguard 
root@zerberus:~# ip link set wg0 up

root@zerberus:~# ifconfig
wg0: flags=209  mtu 1420
        inet  netmask  destination
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 1000  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
All the steps up to here, have to be done on both servers.
My setup was
  • server 1: "public ip", vpn ip
    public wireguard key XXX
    wirguard port: 46932 (how to get this number, just move on)
  • server 2: "public ip", vpn ip
    public wireguard key YYY
    wireguard port: 35891
 To get the public keys and the port number use this command:
root@zerberus:~# wg

interface: wg0
  public key: XXX
  private key: (hidden)
  listening port: 46932
Then use the ip, port and public key from the secondary server:
root@zerberus:~# wg set wg0 peer 23P8GMzwpnpaw38wEERXev1jJIQlkhB/lZB35wwXVD4= allowed-ips endpoint
Do the some on the secondary machine with the ip, port and public key from primary server.

And after that you can check with:
root@zerberus:~# ping

PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=64 time=47.0 ms
64 bytes from icmp_seq=2 ttl=64 time=63.8 ms
--- ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 47.018/55.442/63.866/8.424 ms
I think this was much easier than setting up IPSec or OpenVPN.