Sean, thanks. That worked. Please correct me, the printIndividual( ) is a method in Individual class. So I need to create a class that extends the Individual class so that I could use printIndividual( )? In the owner's manual it stated that genotypeToString( ) should be overridden instead. public class Encoder{ public static void main(String[] args){ System.out.println(ParsingIndividual.genotypeToString()); } } class ParsingIndividual extends Individual{ @Override public String genotypeToString(float f){ return Code.encode(f); } } Rui