This is an interesting article about how some simple one-line changes in some Java code resulted in significant memory performance improvements when running with an old version of Java.
The biggest trick for me to note? Initializing Hash empty objects that never get used. Ever. Why? Well, that’s just what sloppy Java programmers do in big enterprise software.
In my own simple C software, I have always assumed no such sloppiness, and matter of fact I can’t due to the need to support initialize-in-place. But alas, this got to the designers of Java and they did modify later versions of Java to never allocate any memory for an empty Hash set until the first element is avctually written.
20200105/http://blog.pitest.org/how-i-once-saved-half-a-million-dollars-with-a-single-character-code-change/