public Optional<String> apiGroup() {
        return Optional.ofNullable(this.apiGroup);
    }
@return APIGroup is the group for the resource being referenced. If APIGroup is not specified, the specified Kind must be in the core API group. For any other third-party types, APIGroup is required.
sdk/java/src/main/java/com/pulumi/kubernetes/core/v1/outputs/TypedLocalObjectReference.java