GraalVM native executables can run faster than Scala/Java/JVM applications, with much less memory consumption

In two small tests where GraalVM was able to create a native executable, the native executable ran significantly faster than the equivalent Scala/Java code running with the Java 8 JVM, and also reduced RAM consumption by a whopping 98% in a long-running example. On the negative side, GraalVM currently doesn’t seem to work with Swing applications.

Notes on looking at MacOS application/process memory usage alvin July 20, 2019 - 4:14pm

Very briefly, I spent a little time today trying to understand how much memory/RAM a Java/Swing application was really using, and these are my notes from that excursion. Note that the app is bundled as a MacOS/Java app I named AlPad, but from some system perspectives it is only seen by the name JavaAppLauncher. Here are my notes, which will hopefully be useful to me in the future:

Scala: How to give SBT more memory (RAM) to work with

As a brief note, I was trying to run a Scala application inside SBT today and kept getting this “out of memory” error:

[error] (run-main-0) java.lang.OutOfMemoryError: GC overhead limit exceeded
java.lang.OutOfMemoryError: GC overhead limit exceeded

The solution to the problem was to allocate more memory when I start SBT. To give SBT more RAM I first issue this command at the command line:

A Java method to log Android memory use

As a quick note today, here’s a little Java method that I use to log Android memory use (RAM use) from an Activity or Fragment:

private void logMemoryInfo(Context context, String TAG) {
   ActivityManager activityManager = (ActivityManager) context.getSystemService(getActivity().ACTIVITY_SERVICE);
   int memoryClass = activityManager.getMemoryClass();
   ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();

   Log.i(TAG, "\n------------ RAM -------------");
   Log.i(TAG, "mem class: " + memoryClass);
   Log.i(TAG, "mem avail: " + memoryInfo.availMem);
   Log.i(TAG, "low mem:   " + memoryInfo.lowMemory);
   Log.i(TAG, "threshold: " + memoryInfo.threshold);

   long mb = 1024*1024;
   Runtime runtime = Runtime.getRuntime();
   Log.i(TAG, "Used Memory:  " + (runtime.totalMemory() - runtime.freeMemory()) / mb);
   Log.i(TAG, "Free Memory:  " + runtime.freeMemory()  / mb);
   Log.i(TAG, "Total Memory: " + runtime.totalMemory() / mb);
   Log.i(TAG, "Max Memory:   " + runtime.maxMemory()   / mb);
Using the Client JVM and controlling RAM when building a Scala/Java/Mac application alvin November 1, 2014 - 4:16pm

For my TypewriterFX application (which plays Mac OS X typewriter sound effects), I wanted/needed to control the JVM that was used to run the application. The way it works, TypewriterFX plays sounds as fast as it can -- as fast as you type -- so I needed the JVM to be more like the old client JVM than a typical server JVM.