JLink is a pretty nice tool - easy to use and understand, relatively fast, big app size wins. A few misc thoughts: Figuring out what modules you need to ship c

JLink is a pretty nice tool - easy to use and understand, relatively fast, big app size wins. A few misc thoughts: Figuring out what modules you need to ship can be done with the jdeps tool, but, you have to watch out for some gotchas. One is that you have to run it on each JAR or set of jars. It's slow so it helps to do this incrementally. Another is that some critical JVM functions are implemented as 'plugins' that are loaded reflectively, and the static analysis won't find them. The one that trips up my users the most is jdk.crypto.ec which implements elliptic curve cryptography. The Java TLS stack will be present but fail to connect to many TLS servers nearly at random if this module is missing. Nonetheless it still needs less configuration than a typical ProGuard/R8/native-image style dead code elimination analysis. JLink can replace JARs with an optimized file format called "jimage". It uses a very interesting perfect hash algorithm to minimize the number of seeks/page faults required to find a class or file and it also creates a unified string table. So the space savings come not only from deleting dead code but also reducing the space required. Unfortunately it only works for JARs that are explicitly modularized (with a module-info.class file). Slowly more modules are getting this but most still don't. A good improvement would be to use the jimage format for everything. It also does a bunch of other optimizations, for startup time and the like. Also you have to figure out which modules are modular and put them on the module path at link time. There are some build system plugins that can help with that but they mostly don't do cross-linking. Final thing to realize is that jlink doesn't create a bundled app. It just shrinks and customizes the JVM for your app. To allow your app to start up, be installed etc requires other stuff. Conveyor [1] has extensive support for jlink. You can name a JDK or it will learn from your Gradle build, then it'll download the JMOD files you need for each platform, run jdeps on all your JARs incrementally, figure out which modules are explicit, figure out which modules are broken and have to be put on the classpath, add back the TLS ECC support, allow you to override all these decisions via config, run jlink for each target OS and architecture, finally bundle up the results in self-updating packages for each OS and do it all in parallel. It's doing a lot of work but the result is pretty magical - you just take the JARs from your build system e.g. via the Gradle plugin, feed it to the tool and out pops a nicely optimized set of downloads with HTML download page for your cross-platform app. [1] https://hydraulic.software/ https://hydraulic.software/