The code needed is more than you might think. The transitive usage graph is surprisingly dense. FYI I'm one of the original Qt developers, and I remember how it

The code needed is more than you might think. The transitive usage graph is surprisingly dense. FYI I'm one of the original Qt developers, and I remember how it was to try to slim down Qt for embedded use. Java is like that too. The smallest possible program (just a single line to exit) requires things like java.time.chrono.JapaneseChronology. Because argv is a String array, and making the String array requires calling a function or two that can throw exceptions, which requires the Throwable class, which has a static initialiser that requires... the chain is long, but at the end something has a SomethingChronology member, and so AbstractChronology.initCache() is called and mentions JapaneseChronology. A friend of mine tells a story about how how he accidentally FUBARed the tests, and then discovered that running one unit test gave 50% line coverage in Rails. We have big libraries nowadays, and we use them...