//Test.java
public class Test {
// the only purpose of this class is to have a main
  public static void main(String args[]) throws Exception {
    // execution starts here
    // create a target
    BitSequence target = new BitSequence(new int[]{1,1,1,1,1,1});
    System.out.println(target); //check
    BitSequence bs; // declare, do not assign, a BitSequence
    do { // repearedly..
      bs=new BitSequence(); // make a random BitSequence
      System.out.println(bs); // check
    } while (bs.match(target)!=6); // until a perfect match
  }

}

// BitSequence.java
import java.util.BitSet;

// This class models a sequence of bits as a 'chromosome'

public class BitSequence {
static final int bitLength=6; // how many bits - a constant
static int lastID=1; // track ID of last one made
BitSet bits=new BitSet(bitLength); // the class wraps a BitSet
int id; // non-static field, for ID

BitSequence()
{ // constructor - make a random sequence
  for(int i=0; i<bitLength; i++) // for each bit position
    if (Math.random()>0.5) // 50 50 chance
      bits.set(i); // make it a 1
    else bits.clear(i); // else 0
  id=lastID; // set id
  lastID++; // and move on
}

// overloaded constructor
// make a BitSequence from an int array
BitSequence (int[] values) // we do not check the length of values
{
  for(int i=0; i<bitLength; i++) // go through array
    if (values[i]==1)
      bits.set(i); // and set
    else bits.clear(i); // or clear
  id=lastID;
  lastID++;
}

int match(BitSequence other) // count matches between this one and another
{
  int matchCount=0;
  for (int p=bitLength-1; p>-1; p--) // for each bit position
    if (bits.get(p)==other.bits.get(p)) // teh .get returns a boolean
      matchCount++;
  return matchCount;
}

public String toString() // overload Object's toString
{   // so we can print a BitSequence
  StringBuffer sb = new StringBuffer(); // not a String, which is immutable
  sb.append("ID "+id+" : "); // start with the id
  for (int p=bitLength-1; p>-1; p--)
  {
    if (bits.get(p)) // true or false
    sb.append(" 1");
    else sb.append(" 0");
  }
  return sb.toString(); // convert to String

}


}