public String toMutilLineString(){
  final String newLine=System.getProperty("line.separator");
  final StringBuffer problemStr=new StringBuffer();
  for (  final Problem problem : this.problems) {
    problemStr.append(problem.getMessage() + newLine);
  }
  return problemStr.toString();
}

public String toMutilLineString ( ) { final String newLine = System . getProperty ( "line.separator" ) ; final StringBuffer problemStr = new StringBuffer ( ) ; for ( final Problem problem : this . problems ) { problemStr . append ( problem . getMessage ( ) + newLine ) ; } return problemStr . toString ( ) ; }
to mutil line string .
