code: @Override
      @Nullable
      public AccessToken getAccessToken() {
  
          long expiresIn;
          String token;
          Set<String> scopesString;
          String refreshToken;
          String tokenType;
  
          try {
              expiresIn = sharedPreferences.getLong(accessTokenKey + DATE_KEY_SUFFIX, -1);
              token = sharedPreferences.getString(accessTokenKey + TOKEN_KEY_SUFFIX, null);
              scopesString = sharedPreferences.getStringSet(accessTokenKey + SCOPES_KEY_SUFFIX, null);
              refreshToken = sharedPreferences.getString(accessTokenKey + REFRESH_TOKEN_KEY_SUFFIX, null);
              tokenType = sharedPreferences.getString(accessTokenKey + TOKEN_TYPE_KEY_SUFFIX, null);
          } catch (ClassCastException ignored) {
              return null;
          }
  
          if (expiresIn == -1 || token == null || scopesString == null) {
              // Return null, if we can't parse it this token is considered unsaved.
              return null;
          }
  
          Collection<Scope> scopes;
          try {
              scopes = AuthUtils.stringCollectionToScopeCollection(scopesString);
          } catch (IllegalArgumentException ignored) {
              return null;
          }
  
          return new AccessToken(expiresIn, scopes, token, refreshToken, tokenType);
      }
docs: Gets an {@link AccessToken} stored.