for(int i=0;i<s1len;i+=4) { String chunk = s1.substring(i,((i+4) > s1len ? s1len : i+4) );
for(int i=0;i<s1len;i+=BLOCK) { String chunk = s1.substring(i,((i+BLOCK) > s1len ? s1len : i+BLOCK) );
  private int stringDistance( String s1,String s2) {    if( s1 == s2 )      return 0;    if( s1 == null || s1.length() == 0)      return s2.length();    if( s2 == null || s2.length() == 0)      return s1.length();    if( s2.equals(s1) )      return 0;    if( s1.length() > s2.length() ) {      String t= s1; s1=s2;s2=t;    }    int distance = 0;    int s1len =s1.length();    for(int i=0;i<s1len;i+=4) {     String chunk = s1.substring(i,((i+4) > s1len ? s1len : i+4) );      if( s2.indexOf(chunk) == -1 )        distance +=chunk.length();    }//    System.out.println("Distance is " + distance  );//    System.out.println("Lengths " + s2.length() + " and " + s1.length() );    return distance + s2.length()-s1.length();  }