I've been wondering what the exact meaning of [Runtime.getRuntime().totalMemory()][1], [Runtime.getRuntime().freeMemory()][2], and [Runtime.getRuntime().maxMemory()][3] is. My understanding is, `Runtime.getRuntime().totalMemory()` returns the total memory my process is using. Is that correct? How about `freeMemory()` and `maxMemory()`? [1]: https://docs.oracle.com/javase/8/docs/api/java/lang/Runtime.html#totalMemory-- [2]: https://docs.oracle.com/javase/8/docs/api/java/lang/Runtime.html#freeMemory-- [3]: https://docs.oracle.com/javase/8/docs/api/java/lang/Runtime.html#maxMemory--