code: package us.msu.cse.repair.ec.operators.crossover;
  
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.List;
  
  import jmetal.core.Problem;
  import jmetal.core.Solution;
  import jmetal.operators.crossover.Crossover;
  import jmetal.util.Configuration;
  import jmetal.util.JMException;
  import us.msu.cse.repair.ec.representation.ArrayIntAndBinarySolutionType;
  
  public class RandomWithOutCrossover extends Crossover {
  
  	/**
  	 * 
  	 */
  	private static final long serialVersionUID = 1L;
  
  	private static final List<?> VALID_TYPES = Arrays.asList(ArrayIntAndBinarySolutionType.class);
  
  	public RandomWithOutCrossover(HashMap<String, Object> parameters) {
  		super(parameters);
  		// TODO Auto-generated constructor stub
  	}
  
  	public Solution[] doCrossover(Solution parent1, Solution parent2) throws JMException, ClassNotFoundException {
  		Problem problem = parent1.getProblem();
  		Solution[] offSpring = new Solution[2];
  		offSpring[0] = new Solution(problem);
  		offSpring[1] = new Solution(problem);
  		return offSpring;
  	}
  
  	@Override
  	public Object execute(Object object) throws JMException {
  		Solution[] parents = (Solution[]) object;
  
  		if (!(VALID_TYPES.contains(parents[0].getType().getClass())
  				&& VALID_TYPES.contains(parents[1].getType().getClass()))) {
  
  			Configuration.logger_.severe("RandomWithOutCrossover.execute: the solutions "
  					+ "are not of the right type. The type should be 'ArrayIntAndBinary', but " + parents[0].getType()
  					+ " and " + parents[1].getType() + " are obtained");
  
  			Class<?> cls = java.lang.String.class;
  			String name = cls.getName();
  			throw new JMException("Exception in " + name + ".execute()");
  		} // if
  
  		if (parents.length < 2) {
  			Configuration.logger_.severe("RandomWithOutCrossover.execute: operator " + "needs two parents");
  			Class<?> cls = java.lang.String.class;
  			String name = cls.getName();
  			throw new JMException("Exception in " + name + ".execute()");
  		}
  
  		Solution[] offSpring = null;
  		try {
  			offSpring = doCrossover(parents[0], parents[1]);
  			// -> Update the offSpring solutions
  			for (int i = 0; i < offSpring.length; i++) {
  				offSpring[i].setCrowdingDistance(0.0);
  				offSpring[i].setRank(0);
  			}
  		} catch (ClassNotFoundException e) {
  			// TODO Auto-generated catch block
  			e.printStackTrace();
  		}
  
  		return offSpring;
  	} // execute
  
  }
  