public class Data {
    public byte a;
    public byte b;
}

FastSelect<Data> database = new FastSelectBuilder<>(Data.class).create();

// add your data
database.addAll(new ArrayList<Data>(...)); 

MultiGroupCountCallback callback = new MultiGroupCountCallback(fastSelect.getColumnsByNames().get("a"));
database.select(
  new Request[] {new IntRequest("a", new int[]{12, 3})}, 
  callback);
callback.getCounters(); // your result here grouped by field 'a'

FastSelect fastSelect = ...;
final ByteData data = fastSelect.getData("columnWithData");
AggregateCallback<MutableInt> callback = new AggregateCallback<>(
    new Aggregator<MutableInt>() {
        @Override
        public MutableInt create(int position) {
           // will be called when this unique key happens first time
           return new MutableInt(data.data[position]);
        }
        
        @Override
        public void aggregate(MutableInt agg, int position) {
            // will be called all other times
            agg.add(data.data[position]);
        }
    },
    fastSelect.getColumnsByNames().get("aggregationColumn1"),
    fastSelect.getColumnsByNames().get("aggregationColumn2")
    // you can specify any amount of columns with any type
);
fastSelect.select(new Request[0], callback);
Map<AggregateKey, MutableInt> result = callback.getResult();

ListLimitCallback<DemoData> callback = new ListLimitCallback<>(25);
fastSelect.selectAndSort(where, callback, "a");
callback.getResult();

// get ref to real data
IntData id = (IntData) fastSelect.getColumnsByNames().get("id").data;

List<Integer> positions = fastSelect.selectPositions(new Request[] {...});
Collections.sort(positions, new Comparator<Integer>() {
    public int compare(Integer p1, Integer p2) { 
        return id.data[p1] - id.data[p2];
    }
});

// page render
List<Map<String, String>> page = new ArrayList<>();
for (int i = 10; i < 20; i++) {
    int p = positions.get(i);
    Map<String, String> row = new HashMap<>();
    row.put("id", id.data[p]);
    page.add(row);
}

int total = positions.size();

fastSelect.select(new Request[] {
    new IntRequest("id", 12),
    new StringLikeRequest("name", "bim"); // name like '%bim%'
    ...
});

new OrRequest(
    new IntRequest("id", 12),
    new StringLikeRequest("name", "bim"); // name like '%bim%'
)

FastSelect<Object> fastSelect = ...;
FastSelectMXBean fastSelectMXBean = new FastSelectMXBeanImpl(fastSelect);
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
mbs.registerMBean(fastSelectMXBean, new ObjectName("fastselect:type=mbeanname"));

String mbeanName = ...;
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
mbs.unregisterMBean(new ObjectName("fastselect:type=mbeanname"));