This user hasn't shared any biographical information


How to check the expiration date of a ssl certificate?

To check a certificate of an host:

openssl s_client -servername your.domain -connect your.domain:443 2>&- | openssl x509 -enddate -noout | sed 's/^notAfter=//g'

To check a certificate file:

openssl x509 -noout -enddate -in your.crt | sed 's/^notAfter=//g'



Leave a comment

Apache failed on system boot, when binding to an additional IP

Starting point:

My system (Ubuntu 18.04.1) is a VPS running on KVM. The network with some additional IPs is configured with Netplan.



The Apache server is running on an additional IP. If the VPS reboots, the apache didn’t start because, it couldn’t be bind on an aditional IP. A log entry like the following can be found:
apachectl[631]: (99)Cannot assign requested address: AH00072: make_sock: could not bind to address [xxxxxxxx]:80

But if you restart Apache after the reboot, it runs as expected!
Strange, isn’t it?



Ok, I couldn’t find the exact reason of this reason. But I think, there is a strange timing issue on reboot. The network isn’t completely up before Apache is starting.

To solve the problem, just edited the section ‘Unit’ in the file /lib/systemd/system/apache2.service and replace


That’s it!

More information about the network-target can be found her:

, ,

Leave a comment

JII (Java Image Info) Version 1.1.0

Version 1.1.0 of JII has been released.

It provides a clean interface to a collection of Java libraries and source code to read basic properties of images.


  • issue #5 Include Apache-Commons-Imaging
  • issue #8 Update platform to Java 8
  • updated slf4j to 1.7.25
  • changed to maven 3.5

, ,

Leave a comment

How to initialize a static final object

Sometimes I need to intitialize a complex static final object, but I don’t like static blocks for initialization. IMHO it isn’t nice to read!
An alternative way is using an static method:

private static final YourObject defaultYourObject = initYourObject();

private static YourObject initYourObject() {
	try {
		return new YourObject(param1, param2);
	} catch (Exception e) {
		// should never happened
		throw new Error("Could not initialize YourObject", e);

And of course, the error-handling is an own special topic in this case!


Leave a comment

C5Connector.Java Version 0.11

Version 0.11 of the C5Connector.Java has been released.

It’s the Java backend for the filemanager of corefive.

The outstanding feature of this release is that the jar of C5Connector.Java contains the source code of the filemanager. This insures that there aren’t any compatibility issues between C5Connector.Java and the filemanager. We strongly recommend using this feature! The default implementations of the basic interfaces are adapted accordingly.

The changes in detail:

  • issue #39: Adapt FilemanagerConfig to Filemanager 2.5.
  • issue #40: Integrate the filemanager source into the jar file
  • issue #41: New directory with name equals to Parent directory
  • issue #43: The default implementation of FilemanagerCapability should respect if a file is protected
  • issue #44: updated filemanager to 2.5.0
  • issue #45: wrong path in getinfo for folders


This could be one of the last releases of this project. The Filemanager project is deprecated. This is why the future of C5Connector.Java is written in the stars.


Leave a comment