Android apps tend to be compressed for distribution by means Proguard and Pack2000. Not perfect, but it does tree-shaking and so normally you pay only for what

Android apps tend to be compressed for distribution by means Proguard and Pack2000. Not perfect, but it does tree-shaking and so normally you pay only for what you use. I don't really buy the small JAR size argument. In a real project, you care about not reinventing the wheel, so you end up importing needed dependencies anyway, like from apache commons or guava, or stuff for serialization/deserialization, or whatever - I would rather have a couple of hundred KBs extra than having bugs or spending effort on reinventing the wheel. Scala's library for example is pretty big (can't remember the size, 10 or 20 MB?), but it has things I want in it and with tree shaking it can be translated in a dependency of very reasonable size (couple of hundred KB), a technique which also makes feasible Scala.js, a Scala to JS compiler.