private String join(String[] partials,String separator){
  StringBuilder sb=new StringBuilder();
  for (int i=0; i < partials.length; i++) {
    sb.append(partials[i]);
    if (i < partials.length - 1) {
      sb.append(separator);
    }
  }
  return sb.toString();
}

private String join ( String [ ] partials , String separator ) { StringBuilder sb = new StringBuilder ( ) ; for ( int i = 0 ; i < partials . length ; i ++ ) { sb . append ( partials [ i ] ) ; if ( i < partials . length - 1 ) { sb . append ( separator ) ; } } return sb . toString ( ) ; }
joins a string array , with the given separator .
