@JsonProperty
    private Map<String, Object> getMetadata() {
        if (metadata == null) {
            metadata = new HashMap<>();
        }
        
        return metadata;
    }
@ JsonProperty private Map < String , Object > getMetadata ( ) { if ( metadata == null ) { metadata = new HashMap < > ( ) ; } return metadata ; }
Returns the metadata map, creating it if not already so.

@return The metadata map.