Yeah, Doppio needs to download the entire JDK to run, since it&#x27;s a full-featured JVM (JRE for running Java programs, JDK for javac so it can compile them). Compressed, it&#x27;s ~30MB.<p>The authors of this project can preload the JDK with a progress bar and stash it into IndexedDB, since Doppio&#x27;s file system, BrowserFS, supports arbitrary backends [1].<p>[1] <a href="https:&#x2F;&#x2F;github.com&#x2F;jvilk&#x2F;browserfs" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;jvilk&#x2F;browserfs</a>