https://miamao.de/blog genug Unfug Harald Kirsch /blog/2026-02/23.When_is_an_Exception_an_Exception.html Mon, 23 Feb 2026 15:22:05 GMT Recently I said that checked exceptions or not really exceptional . Here is a good example about the tradeoffs. Consider building a directed acyclic graph (DAG), a dependency graph for example. The Node class has a method to add a child: class Node { public void addChild(Node child) { ... } } We must make sure that the graph stays acyclic. So the child node may not be an ancestor of the current node. We add a check to addChild . class Node { public vo /blog/2026-01/22.Moving_Clocks_In_Special_Relativity.html Thu, 22 Jan 2026 15:24:26 GMT $\def\unit#1#2{#1\,\text{#2}}$ What happens to a clock which is moved at some speed for some time. According to special relativity it runs slower on the move. Lets get a bit of an intuitive understanding of this. Moving a light clock from here to there I described the light clock earlier and showed how it runs slower when it is moving. Now, what if we have two identical light clocks, synchronized at some position. Then we move one by a distance $d$ and then stop again. Does /blog/2026-01/11.Twin_Paradox_Explained_with_the_Light_Clock.html Thu, 22 Jan 2026 15:24:33 GMT The Twin Paradox describes how one twin, traveling with non-trivial speed for some time and returning back home, is then younger than his twin. This is explained in detail by Special Relativity physics. See the Wikipedia Twin Paradox page, for example. On this page you find wording like "...clock is running slow...". How's that? The explanation I can grok most easily makes use of the Light Clock . While in the stationary clock, light is bouncing at full speed $c$ /blog/2025-08/31.Black_Holes_Singularity_Seriously.html Thu, 22 Jan 2026 11:34:58 GMT $\def\unit#1#2{#1\,\text{#2}}$ The Car Consider a car with wheels having a circumference of $\unit{1}{m}$, so if the wheel turns around once per second, the car has a speed of one meter per second ($\unit1{m/s}$) or $\unit{3.6}{km/h}$. The car has a somewhat peculiar stop watch on the dashboard. I thas a single hand. The face is divided into 60 like sized parts suggesting that one round of the hand is 60 seconds or one minute. Yet it is mechnically connected to one of the wheels /blog/2025-06/30.Checked_Exceptions_are_not_Exceptions.html Mon, 23 Feb 2026 15:21:37 GMT JavaScript/TypeScript has no checked exceptions and this bothers me. What are "checked exceptions"? As far as I know, Java introduced checked exceptions whereby th signature advertises that function may throw an exception of a specific type. For example OutputStream.write() is declared as: public void write(int b) throws IOException { ... } When another method calls it, it must do one of two things: Use a catch(IOException e) {...} clause to catch and /blog/2024-08/18.A_Practical_Use_for_Regular_Language_Intersection.html Thu, 22 Aug 2024 07:52:39 GMT Long story short: Monqjfa now has an intersection operator . What is "Regular Language Intersection"? A regular language , simply put, is the set of strings you can match with a given regular expression. The regular expressions you find in programming languages or command line programs, though, are often somewhat enhanced with tricks to extend the theoretical setup somewhat. There is a correspondence between pieci /blog/2024-08/03.Tomatenauflauf_mit_Pane_Carasau.html Sat, 3 Aug 2024 09:41:54 GMT Dies ist kein richtiges Rezept, da wir das jedesmal nach Belieben etwas variieren und ich die Zutatenmengen nie wirklich abgewogen habe. Pane Carasau ist ein traditionelles Flatenbrot aus Sardinien. Wir bekommen es manchmal beim italienischen Lebensmittelhändler um die Ecke oder bei unserem Bioshop. Frisch gekauft ist es sehr knusprig, in dem Auflauf wird es schön flauschig. Zutaten Die Mengen sind Schätzungen. 1-2 Lagen pro Auflaufebene Pane Carasau /blog/2024-06/28.Java_Wishlist:_Non_Null_Type_Definitions.html Fri, 28 Jun 2024 08:36:28 GMT Previous entries in my Java Wishlist series: Union Types Thread Safety I hope I don't need to cite the billion dollar mistake or mention that Typescript has explicit null typing? Neither do I need to mention that there are various annotation frameworks which allow to annotate a field or parameter as to whether it may be null or not. Though having half a gazillion frameworks suggests that you want to use none of them for compatibility reasons. The consens /blog/2024-06/16.Java_Wishlist:_Union_Types.html Mon, 24 Jun 2024 15:00:08 GMT This is the 2nd entry in my series about my Java wishlist, the Java features which I would like to see most. Some are already on the JEP list, some are not. The previous entry is: Thread Safety Now lets talk about union types. When programming some non-trivial code in Typescript, I quickly learned to like union types, something like type Stuff = number | boolean | { option: string } And the meaning is pretty much what you expect. When you write function f(stuff: /blog/2024-06/04.Raising_or_Lowering_an_Index.html Mon, 24 Jun 2024 14:57:27 GMT $ \def\ve{\vec{e}} \def\onef{\tilde f} $ First the Rant "You can use the metric to raise an index" is what I found in one or the other physics text book. Surely I missed some context each time, so I couldn't help to swear: WTF, I like the indexes where they are, what is the point of raising or lowering them. It felt like the text was suggesting there is a church of the Oooompf, where physicists gather for rituals during which indices are flipped. But what is the point? /blog/2024-06/04.Java_Wishlist:_Thread_Safety.html Mon, 24 Jun 2024 14:49:31 GMT In the 1990s I felt proud to know Plauger's The Standard C Library nearly by heart, as well as many of the tools C has ready for you to really screw up. Many of the latter gather around fails to do the right thing with bytes provided by memory allocation, malloc() . It was a revelation to start coding in Java. Suddenly I could concentrate on the programming problem to solve, rather than remembering shit like you shall not use scanf("%s", buf) because it may write over the /blog/2024-05/19.Fermi_Paradox,_Yet_Another_Hypothesis.html Mon, 24 Jun 2024 14:46:45 GMT The Fermi Paradox describes the confusing fact that we don't have made contact with alien civilizations despite there being gazillions of galaxies, stars and planets in the universe and we don't have a reason to assume that Earth is extremely special. As Fermi is reported to have put it: "Where is everybody?" For an explanation, Wikipedia lists over 20 hypothesis, one of which is the Zoo Hypothesis whereby aliens avoid us similar to how people avoid wild animals in a zoo: to not /blog/2024-04/18.Geometrized_Units.html Mon, 24 Jun 2024 14:46:09 GMT When reading about theoretical physics, like relativity or quantum mechanics, sooner or later you come across statements like "... with $c=1$ ..." meaning the speed of light is set to be $1$. And similarly, for example with the gravitational constant: $G=1$. This always made me grind my teeth, because: "One? One what?" And also I take some confidence from checking units in a formula for better understanding. If $c$ and $G$ just disappear, this can be quite confusing. Or, as Alan L M /blog/2024-03/06.Kidney-Bohnen_Chili.html Mon, 24 Jun 2024 14:40:57 GMT Das Rezept habe ich selbst "erfunden", obwohl natürlich klar ist, dass ich das in ähnlicher Form irgendwo gegessen oder gelesen habe. Die Kombination von Bohnen, Tomaten, scharf gewürzt und etwas Sähmigkeit durch den Feta ist sehr lecker. Aufpassen: der Feta und je nach Marke auch die Bohnen aus der Dose bringen bereits Salz ins Gericht. Wenn das nicht reicht, lieber erst auf dem Teller nachsalzen. Zutaten für 2 Personen 2 Zwiebel 1 rote Paprika 1/2 Staude /blog/2024-02/24.Wickeln_wir_die_reelle_Achse_um_einen_Kreis.html Mon, 24 Jun 2024 14:39:47 GMT Vorgeplänkel Die reellen Zahlen, $\RB$, sind schon ein wenig komisch, im Vergleich zu den rationalen Zahlen $\QB$. Zur Erinnerung, $\QB$ sind die Zahlen die sich als Brüche von ganze Zahlen ergeben, sowas wie $7/9$, $1/3$ oder $31415926/10000000$. Man kann sie auch dadurch beschreiben, dass ihre Darstellung als Dezimalzahl hinter dem Komma nach hinten raus periodisch wird, das heißt dieselbe Ziffernfolge wiederholt sich unendlich oft. Die Zahl $1{,}3$ is formal gleich $1{,}30000....$ und /blog/2024-02/19.Configuring_Java_formatting_with_Emacs_lsp-mode.html Mon, 24 Jun 2024 14:38:39 GMT Continuing the series about of configuring Emacs as a Java development IDE , lets talk about code formatting. Emacs' lsp-mode uses the Eclipse language server to stay informed about the Java code being edited. This also includes the server's service to format part or all of the Java code according to some rules. It employs Eclipse's code formatter which has lots of options. When using the Eclipse UI, these can be tweaked visually in an extensive settings screen. To use thes /blog/2024-02/15.Starting_with_emacs_lsp-mode_for_Java_development.html Mon, 24 Jun 2024 14:36:02 GMT First the Rant In ancient times (the 1980s) I learned programming mostly using Emacs and some key bindings got chiseled into my brain forever. When I started Java programming in Emacs, support for coding actions based on compiler output, like quick fixes suggestions, was not available, sadly. So I switched to Eclipse for Java programming. But my first action was to enable Emacs key bindings as far as available. Only recently, around 2019, I switched mostly to Intellij, because around /blog/2024-02/12.Good_Log_Messages.html Mon, 24 Jun 2024 14:32:22 GMT In my previous jobs I also had to analyse log messages for which I did not have the code readily available. Besides intentionally idiotic messages like "trouble in paradise", I had my fair share of message that made me grind my teeth. They read like: could not open file could not connect error parsing These were the full texts, seriously. Why does the idiot not list the file it can't open? Why can't they just tell me which crap they can't parse? Had the information been /blog/2024-02/03.Käsefondue.html Mon, 24 Jun 2024 14:31:24 GMT Das Rezept habe ich irgendwo gefunden, minimal abgewandelt und so funktioniert es für uns immer perfekt. Zutaten für 2 Personen 200g Greyezer/Gruyere eher mittelalt, etwas teurer 100g Emmentaler 100g Appenzeller eher mittelalt, etwas teurer 1 Knoblauchzehe 200ml Weißwein trocken 20ml Kirschwasser 1,5 EL Mondamin 1 Messerspitze Natron 1 Baguette Zubereitung Käse grob hobeln Kirschwasser und Mondamin mischen un /blog/2024-01/15.Bolaggio,_italienischer_Eintopf,_Variation.html Sat, 3 Feb 2024 18:42:46 GMT Im Original wird das Rezept mit Schweinefleich formuliert, Bauch und Schulter. Zutaten für 4 Portionen 500g Lammgulasch 2 Zwiebeln 250g Möhren 1 Weißkohl (ca. 600g) 2 Zehen Knoblauch 3 El Olivenöl 400g-Dose Tomaten stückig 360g-Glas kleine weiße Bohnen 250ml Fleischbrühe aus fertiger Rinderbouillon Peffer, Thymian, Rosmarin, Paprika edelsüß, Chiliflocken 1 Bund Petersilie Zubereitung Zwiebeln, Möhre