Not getting refresh token expired error message

[sarathn91]

When I pass a invalid refresh token I'm not getting the message which I'm supposed to get which is :

{"errors":[{"errorType":"oauth","fieldName":"refresh_token","message":"Refresh token invalid: XXXXX"}],"success":false}

instead my program crasahes at the line where I make the request. Can someone look into my code and tell me What I'm doing wrong. When I pass a correct refresh token everything is working fine.

Thank you. 

Here's my code:

public static String getAccessTokenFromRefreshToken(int accountId, Connection connection, int accountDeviceId, String refreshToken, String accessToken) throws Exception {
	String newAccessToken = null;
	OAuthJSONAccessTokenResponse oAuthResponse = null;
	try {
		OAuthClientRequest request = OAuthClientRequest
				.tokenLocation(FITBIT_TOKEN_URI)
				.setGrantType(GrantType.REFRESH_TOKEN)
				.setRefreshToken(refreshToken).buildBodyMessage();
			
		Map<String, String> headers = new HashMap<String, String>();
		headers.put(OAuth.HeaderType.AUTHORIZATION, "Basic " + "~ ~");
		headers.put(OAuth.HeaderType.CONTENT_TYPE, "application/x-www-form-urlencoded");
		request.setHeaders(headers);
			

		OAuthClient oAuthClient = new OAuthClient(new URLConnectionClient());
		oAuthResponse = oAuthClient.accessToken(request); // program goes to catch block from here while I'm expecting oAuthResponse to contain the above error message (invalid refresh token message)

                log.debug("response: " + oAuthResponse.getBody()); // not getting printed..
		Map<String, Object> tokenMap = convertJsonToMap(oAuthResponse.getBody());
		newAccessToken = tokenMap.get("access_token").toString();
		refreshToken = tokenMap.get("refresh_token").toString();
		String userId =  tokenMap.get("user_id").toString();
		String expiresIn = tokenMap.get("expires_in").toString();
	
		updateOAuthCredentials(accountDeviceId, newAccessToken, refreshToken, connection);

	} catch (Exception e) {
		log.debug("inside catch");
	}
	return newAccessToken;
}