018081.{2019-10-29_21.56.28}{unknown}{unknown}.txt

class TestGC {
    private static Runtime rt = Runtime.getRuntime();

    private static long free() { return rt.maxMemory() - rt.totalMemory() + rt.freeMemory(); }

    public static void main(String[] args) throws InterruptedException, IOException {
        int blocks = 50;
        int typeSize = 8;
        long initiallyFree = free();
        System.out.println("initially free: " + initiallyFree / 1000000);
        ArrayList data = new ArrayList();
        for (int n = 0; n < blocks; n++) {
            data.add(new long[1024 * 1024-2]);
        }
        System.gc();
        Thread.sleep(500);
        long remainingFree = free();
        System.out.println("remaining free: " + remainingFree / 1000000);
        System.out.println("used: " + (initiallyFree - remainingFree) / 1000000);
        System.out.println("expected usage: " + blocks * typeSize);
    }
}