Test of Java memory consumption

MemoryTests.java

/**
 * Test memory consumption and garbage collection over time.
 * Copyright (C) 2012 Matt Conway. Licensed under the Apache 2 license.
 */

import java.util.ArrayList;

public class MemoryTests {
   public static void main (String[] args) 
          throws InterruptedException {
      // don't do this on each iteration
      Runtime rt = Runtime.getRuntime();

      ArrayList<Integer> arrayList;
      short iterations = 0;
      double usedMem, totalMem;

      // loop until killed
      while (true) {
         arrayList = getArrayList();
         iterations++;
         
         Thread.sleep(500);

         if (iterations == 120) {
            iterations = 0; // don't let it get filled up
            
            // stackoverflow
            totalMem = rt.totalMemory() / 1024;
            usedMem = (rt.totalMemory() - rt.freeMemory()) / 1024;

            System.out.println(
               String.format("%.2f / %.2f KB", usedMem, totalMem)
            );
         }
      }
   }
   
   private static ArrayList<Integer> getArrayList () {
      ArrayList<Integer> arrayList = new ArrayList<Integer>();
      for (int i = 0; i < 1000; i++) {
         arrayList.add((Integer) i);
      }
      return arrayList;
   }
}