Rest API data get post:

        Retrofit retrofit = new Retrofit
                            .Builder()
                            .baseUrl(Constant.base_url)
                            .addConverterFactory(GsonConverterFactory.create())
                              .build();


        retrofitClient = retrofit.create(RetrofitClient.class);

        Call<OurMainDataClass> call = retrofitClient.getData(Constant.api_token);

        call.enqueue(new Callback<OurMainDataClass>() {
            @Override
            public void onResponse(Call<OurMainDataClass> call, Response<OurMainDataClass> response) {

                if (response.isSuccessful())
                {
                    allcontinentslist=response.body().getData();

                    continents_adapter=new Continents_Adapter(MainActivity.this,MainActivity.this,allcontinentslist);
                    // recyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
                    recyclerView.setHasFixedSize(true);
                    recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
                    recyclerView.setAdapter(continents_adapter);
                    continents_adapter.notifyDataSetChanged();

                    for (Continents continents:allcontinentslist)
                    {
                        Log.d("resource",continents.getResource());
                        Log.d("id",String.valueOf(continents.getId()));
                        Log.d("name",continents.getName());
                        Log.d("updated_at",continents.getUpdated_at());

                    }


                }

            }

            @Override
            public void onFailure(Call<OurMainDataClass> call, Throwable t) {

                Log.d("failed","not data fetch");
            }
        });

package ruhulbdapp.com.blogspot;

import retrofit2.Call;
import retrofit2.http.GET;
import retrofit2.http.Query;

public interface RetrofitClient {
 
    @GET("continents")
    Call<OurMainDataClass> getData(@Query("api_token") String token);

}

Post request---------------------------------------

Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("https://jsonplaceholder.typicode.com/")
        .addConverterFactory(GsonConverterFactory.create())
        .build();

lastLoginObject = new LastLoginObject("dateTime|UNIX", "172.242.228.245");
dataObjectClass = new dataObjectClass("555", "internetEmail", "personGender", "name", lastLoginObject);

MainObjectClass mainObjectClass =  new MainObjectClass("MPSfLPolMP80AQJpPc5cYQ",dataObjectClass);
OurRetrofitClient ourRetrofitClient = retrofit.create(OurRetrofitClient.class);
Call<MainResponseObjectClass> res = ourRetrofitClient.GetPostValue(mainObjectClass);

  res.enqueue(new Callback<MainResponseObjectClass>() {
      @Override
      public void onResponse(Call<MainResponseObjectClass> call, Response<MainResponseObjectClass> response) {

                 String email =    response.body().getEmail();
                 String Name =    response.body().getName();
                 String Gender =    response.body().getGender();
                 String Id =    response.body().getId();
                 LastLoginObject object = response.body().getLast_login();

                 String time =         object.getDate_time();
                 String ip =         object.getIp4();

                 Log.d("name",Name);
                 Log.d("email",email);
                 Log.d("email",email);
                 Log.d("Id",Id);
                 Log.d("time",time);
                 Log.d("ip",ip);

      }

      @Override
      public void onFailure(Call<MainResponseObjectClass> call, Throwable t) {
          Log.d("response","fail");
      }
  });

OurRetrofitClient------------------------------

@POST("q")
Call<MainResponseObjectClass> GetPostValue(@Body MainObjectClass mainObjectClass);