This has a lot more to do with the GUI toolkits than the JVM. Python is most often used with bindings for GTK (C), QT (C++) or tk (C). I don't know a lot abou

This has a lot more to do with the GUI toolkits than the JVM. Python is most often used with bindings for GTK (C), QT (C++) or tk (C). I don't know a lot about .net but I believe it just links to the standard windows gui toolkit probably also written in native code. For Java the main issue is that Swing/SWT/AWT suck and java is mostly used as a server language so there is little impetus to fix them. Eclipse is just bloated, that is why its often slow. Android has its own custom JVM (Dalvik) but I imagine the majority of the UI rendering / handling code is native with Java bindings. All that said, the full JVM (both openJDK and sun's) have multiple garbage collectors and many tuning options. This creates flexibility to tune the GC for particular work loads but also makes them complicated to work with. It doesn't help that the default GC/memory settings in the JVM are a bit...off, and use the high throughput GC vs the low pause collectors.