assertEquals("1.024EB", MemoryUtil.byteCountToDisplaySize(FileUtils.ONE_EB));
    }

    public void test_getUsedMemory() {
        assertTrue(MemoryUtil.getUsedMemory() >= 0);
    }

    public void test_sizeOf() throws Exception {
        // System.out.println("size: " + getObjectSize(""));
        assertEquals(24L, MemoryUtil.sizeOf(Integer.MAX_VALUE));

            displaySize = new BigDecimal(size).divide(BigDecimal.valueOf(1000)) + "KB";
        } else {
            displaySize = size + "bytes";
        }
        return displaySize;
    }

    public static long getUsedMemory() {
        final Runtime runtime = Runtime.getRuntime();
        final long freeBytes = runtime.freeMemory();
        final long totalBytes = runtime.totalMemory();
        return totalBytes - freeBytes;
    }

        long margin = 5000000L;
        System.gc();
        for (int i = 0; i < 30; i++) {
            if (MemoryUtil.getUsedMemory() < current + margin) {
                break;
            }
            System.gc();
            Thread.sleep(1000L);
        }
        final long usedMemory = MemoryUtil.getUsedMemory();