osMemoryObj.physical = osMemoryPhysicalObj;
        osMemoryPhysicalObj.free = osProbe.getFreePhysicalMemorySize();
        osMemoryPhysicalObj.total = osProbe.getTotalPhysicalMemorySize();
        final OsMemorySwapSpaceObj osMemorySwapSpaceObj = new OsMemorySwapSpaceObj();
        osMemoryObj.swapSpace = osMemorySwapSpaceObj;
        osMemorySwapSpaceObj.free = osProbe.getFreeSwapSpaceSize();

        buf.append("\"memory\":{");
        buf.append("\"physical\":{");
        append(buf, "free", () -> osProbe.getFreePhysicalMemorySize()).append(',');
        append(buf, "total", () -> osProbe.getTotalPhysicalMemorySize());
        buf.append("},");
        buf.append("\"swap_space\":{");
        append(buf, "free", () -> osProbe.getFreeSwapSpaceSize()).append(',');

    String SUGGEST_POPULAR_WORD_WINDOW_SIZE = "suggest.popular.word.window.size";

    /** The key of the configuration. e.g. 10 */
    String SUGGEST_POPULAR_WORD_QUERY_FREQ = "suggest.popular.word.query.freq";

    /** The key of the configuration. e.g. 1 */
    String SUGGEST_MIN_HIT_COUNT = "suggest.min.hit.count";

    /** The key of the configuration. e.g. _default */