title: Angular 7 : Injected service is undefined
body: <p>I tried to inject AccountService in the LoginService but it won't ,the accountService is undefined but in the other hand the authServiceProvider is defined . </p>
  
  <p>Contrarily it injected perfectly in footerComponent.</p>
  
  <p>So why the AccountService is injected perfectly in FooterComponent and it bugs in the LoginService.</p>
  
  <p>I do not know where the problem came from . </p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { AccountService } from 'app/core/auth/account.service';
  import { AuthServerProvider } from 'app/core/auth/auth-jwt.service';
  @Injectable({ providedIn: 'root' })
  export class LoginService {
      constructor(public accountService: AccountService, private authServerProvider: AuthServerProvider) {
          console.log(this.accountService); //  is undefined 
          console.log(this.authServerProvider); // is defined
  }
  </code></pre>
  
  <p>This is the AuthentificationService</p>
  
  <pre><code>@Injectable({ providedIn: 'root' })
  export class AuthServerProvider {
      constructor(private http: HttpClient, private $localStorage: LocalStorageService, private $sessionStorage: SessionStorageService) {}
  </code></pre>
  
  <p>This is the AccountService</p>
  
  <pre><code>@Injectable({ providedIn: 'root' })
  export class AccountService {
      private userIdentity: any;
      private authenticated = false;
      private authenticationState = new Subject&lt;any&gt;();
      constructor(private languageService: JhiLanguageService, private sessionStorage: SessionStorageService, private http: HttpClient) {}
  </code></pre>
  
  <p>I tried to use AccountService in other component and it injected perfectly </p>
  
  <pre><code>import { Component } from '@angular/core';
  import { AccountService } from 'app/core';
  @Component({
      selector: 'jhi-footer',
      templateUrl: './footer.component.html',
      styleUrls: ['./footer.component.scss']
  })
  export class FooterComponent {
  
      constructor( private accountService: AccountService) {
          console.log(this.accountService); // It is defined
  
      }
  }
  </code></pre>
  
  <p>this is the app.module.ts</p>
  
  <pre><code>import './vendor.ts';
  import { NgModule } from '@angular/core';
  import { BrowserModule } from '@angular/platform-browser';
  import { HTTP_INTERCEPTORS } from '@angular/common/http';
  import { NgbDatepickerConfig } from '@ng-bootstrap/ng-bootstrap';
  import { Ng2Webstorage } from 'ngx-webstorage';
  import { NgJhipsterModule } from 'ng-jhipster';
  import { AuthInterceptor } from './blocks/interceptor/auth.interceptor';
  import { AuthExpiredInterceptor } from './blocks/interceptor/auth-expired.interceptor';
  import { ErrorHandlerInterceptor } from './blocks/interceptor/errorhandler.interceptor';
  import { NotificationInterceptor } from './blocks/interceptor/notification.interceptor';
  import { SharedModule } from 'app/shared';
  import { CoreModule } from 'app/core';
  import { AppRoutingModule } from './app-routing.module';
  import { HomeModule } from './home/home.module';
  import { AccountModule } from './account/account.module';
  import { EntityModule } from './entities/entity.module';
  import * as moment from 'moment';
  // jhipster-needle-angular-add-module-import JHipster will add new module here
  import { JhiMainComponent, NavbarComponent, FooterComponent, PageRibbonComponent, ActiveMenuDirective, ErrorComponent } from './layouts';
  @NgModule({
      imports: [
          BrowserModule,
          Ng2Webstorage.forRoot({ prefix: 'jhi', separator: '-' }),
          NgJhipsterModule.forRoot({
              // set below to true to make alerts look like toast
              alertAsToast: false,
              alertTimeout: 5000,
              i18nEnabled: true,
              defaultI18nLang: 'en'
          }),
          SharedModule.forRoot(),
          CoreModule,
          HomeModule,
          AccountModule,
          // jhipster-needle-angular-add-module JHipster will add new module here
          EntityModule,
          AppRoutingModule
      ],
      declarations: [JhiMainComponent, NavbarComponent, ErrorComponent, PageRibbonComponent, ActiveMenuDirective, FooterComponent],
      providers: [
          {
              provide: HTTP_INTERCEPTORS,
              useClass: AuthInterceptor,
              multi: true
          },
          {
              provide: HTTP_INTERCEPTORS,
              useClass: AuthExpiredInterceptor,
              multi: true
          },
          {
              provide: HTTP_INTERCEPTORS,
              useClass: ErrorHandlerInterceptor,
              multi: true
          },
          {
              provide: HTTP_INTERCEPTORS,
              useClass: NotificationInterceptor,
              multi: true
          }
      ],
      bootstrap: [JhiMainComponent]
  })
  export class AppModule {
      constructor(private dpConfig: NgbDatepickerConfig) {
          this.dpConfig.minDate = { year: moment().year() - 100, month: 1, day: 1 };
      }
  }
  </code></pre>
  
  <p>and this is the core.module .</p>
  
  <pre><code>import { NgModule, LOCALE_ID } from '@angular/core';
  import { DatePipe, registerLocaleData } from '@angular/common';
  import { HttpClientModule } from '@angular/common/http';
  import { Title } from '@angular/platform-browser';
  import locale from '@angular/common/locales/en';
  @NgModule({
      imports: [HttpClientModule],
      exports: [],
      declarations: [],
      providers: [
          Title,
          {
              provide: LOCALE_ID,
              useValue: 'en'
          },
          DatePipe
      ]
  })
  export class CoreModule {
      constructor() {
          registerLocaleData(locale);
      }
  }
  </code></pre>
  
  <p>Thanks in advance for your help.</p>