public static String insert(final String value,final String substr,final int index){
  validate(value,NULL_STRING_PREDICATE,NULL_STRING_MSG_SUPPLIER);
  validate(substr,NULL_STRING_PREDICATE,NULL_STRING_MSG_SUPPLIER);
  if (index > value.length()) {
    return value;
  }
  return append(value.substring(0,index),substr,value.substring(index));
}

public static String insert ( final String value , final String substr , final int index ) { validate ( value , NULL_STRING_PREDICATE , NULL_STRING_MSG_SUPPLIER ) ; validate ( substr , NULL_STRING_PREDICATE , NULL_STRING_MSG_SUPPLIER ) ; if ( index > value . length ( ) ) { return value ; } return append ( value . substring ( 0 , index ) , substr , value . substring ( index ) ) ; }
inserts ' substr ' into the ' value ' at the ' index ' provided .
