Gokhan

import java.util.*;
import javax.ws.rs.*;
import javax.ws.rs.core.*;


@ApplicationPath("/")
public class ApplicationConfig extends Application {
    @Override
    public Set<Class<?>> getClasses(){
        Set<Class<?>> set =new HashSet<>();
        set.add(MyResource.class);
        return set;
    }
    @Override
    public Set<Object> getSingletons(){
        Set<Object> set=new HashSet<>();
        set.add(new MySingletonResource());
        return set;
    }
    
}

Gokhan1

import javax.ws.rs.GET;
import javax.ws.rs.Path;

@Path("/")
public class MyResource {
  private int counter;

  @GET
  @Path("count1")
  public void count() {
       counter++;
  }

  @GET
  @Path("counter1")
  public int getCounter() {
      return counter;
  }

  @GET
  @Path("reset1")
  public void reset() {
      counter = 0;
  }
}

Gokhan2

import javax.ws.rs.GET;
import javax.ws.rs.Path;

@Path("/")
public class MySingletonResource {
  private int counter;

  @GET
  @Path("count2")
  public void count() {
      counter++;
  }

  @GET
  @Path("counter2")
  public int getCounter() {
      return counter;
  }

  @GET
  @Path("reset2")
  public void reset() {
      counter = 0;
  }
}

Gokhan3

import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.WebTarget;

public class MyClient1 {
  public static void main(String[] args) {
      getRequest("/reset1", Void.class);
      countRequest("/count1");
      Integer counter = getRequest("/counter1", Integer.class);
      System.out.printf("counter1: %s%n", counter);

      getRequest("/reset2", Void.class);
      countRequest("/count2");
      Integer counter2 = getRequest("/counter2", Integer.class);
      System.out.printf("counter2: %s%n", counter2);
  }

  public static void countRequest(String uri) {
      for (int i = 0; i < 10; i++) {
          getRequest(uri, Void.class);
      }
  }
  
  public static <T> T getRequest(String uri, Class<T> responseType) {
      Client client = ClientBuilder.newClient();
      WebTarget target = client.target("http://localhost:8080" + uri);
      return target.request().get(responseType);
  }
}