RESTful with Vert.x

LinguisticsServer.java

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.vertx.java.core.Handler;
import org.vertx.java.core.Vertx;
import org.vertx.java.core.VertxFactory;
import org.vertx.java.core.buffer.Buffer;
import org.vertx.java.core.http.HttpServerRequest;
import org.vertx.java.core.http.RouteMatcher;

import java.io.IOException;

public class LinguisticsServer {
    private final static Logger logger = LoggerFactory.getLogger(LinguisticsServer.class);
    protected Vertx vertx = VertxFactory.newVertx();
    private static LinguisticsServer instance = null;
    private RouteMatcher routeMatcher;

    /**
     * Constructor
     */
    private LinguisticsServer(){
        this.initialize();
    }

    /**
     * Singleton pattern
     * @return  The current & only instance
     */
    public synchronized static LinguisticsServer getInstance() {
        if(instance == null){
            instance = new LinguisticsServer();
        }
        return instance;
    }

    private void initialize(){
        routeMatcher = new RouteMatcher();

        routeMatcher.get("/users/get", new Handler<HttpServerRequest>() {
            public void handle(HttpServerRequest request) {
                //Get user and write to response
            }
        });

        routeMatcher.post("/users/create", new Handler<HttpServerRequest>() {
            public void handle(final HttpServerRequest request) {
                //Create user and write to response
                int i =0;
                request.expectMultiPart(true);
                
                // handle form data
                request.endHandler(new Handler<Void>() {
                    @Override
                    public void handle(Void aVoid) {
                        String uname = request.formAttributes().get("username");
                        String upass = request.formAttributes().get("password");

                        System.out.println(uname + " " + upass);
                        request.response().end();
                    }
                });
                
                // handle body raw data
                request.bodyHandler(new Handler<Buffer>() {
                    @Override
                    public void handle(Buffer buffer) {
                        int i = 0;
                    }
                });

            }
        });

        routeMatcher.put("/users/update", new Handler<HttpServerRequest>() {
            public void handle(HttpServerRequest request) {
                //Update user and write to response
            }
        });

        routeMatcher.delete("/users/delete", new Handler<HttpServerRequest>() {
            public void handle(HttpServerRequest request) {
                //Delete user and write to response
            }
        });
    }

    /**
     * Activate the server
     */
    public void run() {

        vertx.createHttpServer()
                .requestHandler(routeMatcher)
                .listen(8080);

        try {
            System.in.read();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    public static void main(String[] args) {
        getInstance().run();
    }

}