private Map<String, CasUserAccount> readAccountsFromResource() throws PreventedException {
        try (val in = resource.getInputStream()) {
            return MAPPER.readValue(in,
                new TypeReference<>() {
                });
        } catch (final Exception e) {
            LoggingUtils.error(LOGGER, e);
            throw new PreventedException(e);
        }
    }
This is {@link JsonResourceAuthenticationHandler}.

@author Misagh Moayyed
@since 5.3.0
support/cas-server-support-generic/src/main/java/org/apereo/cas/adaptors/generic/JsonResourceAuthenticationHandler.java