@Beta
    public void onCreateProxy() {
        if (!isAllowProxy()) {
            throw new IllegalStateException(
                    "Creating onDemand proxy disallowed. Ensure @GenerateSqlObject annotation is being processed by `jdbi3-generator` annotation processor.");
        }
    }
Throw if proxy creation is disallowed.
core/src/main/java/org/jdbi/v3/core/extension/Extensions.java