### Question:
OAuthJSONAccessTokenResponse extends OAuthAccessTokenResponse { @Override public String getAccessToken() { return getParam(OAuth.OAUTH_ACCESS_TOKEN); } OAuthJSONAccessTokenResponse(); @Override String getAccessToken(); @Override String getTokenType(); @Override Long getExpiresIn(); String getScope(); OAuthToken getOAuthToken(); String getRefreshToken();  }### Answer:
@Test public void testGetAccessToken() throws Exception { OAuthJSONAccessTokenResponse r = null; try { r = new OAuthJSONAccessTokenResponse(); r.init(TestUtils.VALID_JSON_RESPONSE, OAuth.ContentType.JSON, 200); } catch (OAuthProblemException e) { fail("Exception not expected"); } Assert.assertEquals(TestUtils.ACCESS_TOKEN, r.getAccessToken()); try { r = new OAuthJSONAccessTokenResponse(); r.init(TestUtils.ERROR_JSON_BODY, OAuth.ContentType.JSON, 200); fail("Exception expected"); } catch (OAuthProblemException e) { Assert.assertNotNull(e.getError()); } }