public Source retrieveSourceSynchronous(
            @NonNull @Size(min = 1) String sourceId,
            @NonNull @Size(min = 1) String clientSecret)
            throws AuthenticationException,
            InvalidRequestException,
            APIConnectionException,
            APIException {
        return retrieveSourceSynchronous(sourceId, clientSecret, null);
    }
public Source retrieveSourceSynchronous ( @ NonNull @ Size ( min = 1 ) String sourceId , @ NonNull @ Size ( min = 1 ) String clientSecret ) throws AuthenticationException , InvalidRequestException , APIConnectionException , APIException { return retrieveSourceSynchronous ( sourceId , clientSecret , null ) ; }
Retrieve an existing {@link Source} from the Stripe API. Note that this is a
synchronous method, and cannot be called on the main thread. Doing so will cause your app
to crash. This method uses the default publishable key for this {@link Stripe} instance.

@param sourceId the {@link Source#mId} field of the desired Source object
@param clientSecret the {@link Source#mClientSecret} field of the desired Source object
@return a {@link Source} if one could be found based on the input params, or {@code null} if
no such Source could be found.

@throws AuthenticationException failure to properly authenticate yourself (check your key)
@throws InvalidRequestException your request has invalid parameters
@throws APIConnectionException failure to connect to Stripe's API
@throws APIException any other type of problem (for instance, a temporary issue with
Stripe's servers)