IT Sky Consulting GmbH
This year I have had the pleasure to visit the Devoxx-Conference in Antwerp in Belgium. I have visited the following talks: Day 1: Opening Keynote Session about Java 9 modules Keynote Session about the beginning of the Universe Asynchronous programming in Java 8: how to use CompletableFuture by José Paumard Ignite Sessions I JRuby 9000 …
Many software systems rely on some kind of unique numbers. Uniqueness is always a question in what universe this uniqueness is required. We do see the different kinds of universes in the case of the IP-addresses. In theory they are world wide unique. In practice we have mechanisms in place like NAT, that use certain …
„Creating Unique Numbers“ weiterlesen
Deutsch Introduction When running a Linux system in its graphical mode, keyboard mappings can be changed by using xmodmap. Each key on the keyboard has a „keycode“ which can be found out by looking at the output of xmodmap -pke > current-keyboard or by running xev for trying out the keys. I am using a …
„Changing of Keyboard Mappings with xmodmap“ weiterlesen
This singleton pattern is not really a big deal, but overused because it gives us the coolness of knowing about design patters without learning too much stuff for that… It does have its uses in some programming languages, while more or less implicit or obsolete in others, depending on the point of view. I have …
„Java: Using Enums for Singletons“ weiterlesen
What we do in IT is programming and implementing and maintaining automatism. The general usefulness is not really challenged these days, but it was quite a big deal a few decades ago. Many routine tasks can be done more efficiently and more reliably or become feasible at all with IT… Just think of getting money …
„Automation and its Limits“ weiterlesen
Deutsch Whoever is working with MS-Windows, should know these black windows with CMD running in them, even though they are not really popular. The Unix and Linux guys hate them, because they are really primitive compared to their shells. Windows guys like to work graphically. Or they prefer powershell or bash with cygwin. Linux and …
„MS-Windows-Encodings with CMD: Bug or Feature?“ weiterlesen
When writing word press articles and including example code with <code>, the leading spaces are discarded when the article is displayed and without indention code looks weird and unreadable. A way to bypass this is to transform tabs to spaces, and then replace all spaces by no-break-spaces (unicode 0x00A0). Then the indention remains intact. Direct …
„Code examples in WordPress“ weiterlesen
Deutsch This Singleton Pattern has the advantage to be easy to memorize. The only really interesting aspect of it is the issue of initialization („lazy or „eager“) and maybe the dependencies between multiple singletons. But I would like to mention two generalizations. A Singleton exists once in the whole program. Generalizations can address the uniqueness …
„Design Patterns: Singleton“ weiterlesen
When Java came out about 20 years, it was great to have a decent and quite extensive collection library available as part of the standard setup and ready to use. Before that we often had to develop our own or find one of many interesting collection libraries and when writing and using APIs it was …
„Using Collections“ weiterlesen
Additional indices („indexes“ in Oracle’s English) apart from the primary key are extremely important for the performance of databases. There is this magic behind it, when a complicated query with multiple joins runs slowly and magically becomes faster when adding the right index and the right hint or does not become faster at all, even …
„Indexing of Database Tables II (additional indices)“ weiterlesen