Instance variables are the same in each object initialization

Question

I'm making a genetic algorithm that deals with evolving an array of chars into "Hello World". The problem is whenever I initialize a Chromosome object and call the generateChromosome method, all the chromosomes of "test" population remains the same?

public class Chromosome{
   private static int defaultLength = 11;
   private static char []genes = new char[defaultLength]; <--- this remains the same for each object :/


   //Generates a random char chromosome
   public void generateChromosome(){
      char []newGene =  new char[defaultLength];
      for(int x = 0; x<size(); x++){
         char gene = (char)(32+Math.round(96*Math.random()));
         newGene[x] = gene;

      }
      genes = newGene;

   }

   //Returns a specific gene in the chromosome
   public char getGene(int index){
     return genes[index];
   }

   public char[] getChromosome(){
      return genes;
   }

   public void setGene(char value, int index){

   genes[index] = value;

   }

   public static  void setDefaultLength(int amount){
      defaultLength = amount;
   }

   public static int getDefaultLength(){
      return defaultLength;
   }

   public int size(){
      return genes.length;
   }

   @Override
   public String toString(){
      String geneString = "";
      for(int x= 0; x<genes.length; x++){
         geneString += genes[x];
      }
      return geneString;
   }
}

Answer 1

That's because your variables are static, i.e. class variables. They will be the same in each instantiation of your class.

If you want an instance variable, remove the static keyword.