The following two lines in Oidc#sendJsonHttpRequest are missing the throw keyword at the beginning:

https://github.com/wildfly-security/wildfly-elytron/blob/1.x/http/oidc/src/main/java/org/wildfly/security/http/oidc/Oidc.java#L117

https://github.com/wildfly-security/wildfly-elytron/blob/1.x/http/oidc/src/main/java/org/wildfly/security/http/oidc/Oidc.java#L121

Update these two lines to add the throw keyword.