@CustomType.Setter
        public Builder key(String key) {
            if (key == null) {
              throw new MissingRequiredPropertyException("SecretKeySelector", "key");
            }
            this.key = key;
            return this;
        }
@return Specify whether the Secret or its key must be defined
sdk/java/src/main/java/com/pulumi/kubernetes/core/v1/outputs/SecretKeySelector.java