public Factory(JavacMessages messages,String prefix){
  this.prefix=prefix;
  this.formatter=new BasicDiagnosticFormatter(messages);
  defaultErrorFlags=EnumSet.of(DiagnosticFlag.MANDATORY);
}

public Factory ( JavacMessages messages , String prefix ) { this . prefix = prefix ; this . formatter = new BasicDiagnosticFormatter ( messages ) ; defaultErrorFlags = EnumSet . of ( DiagnosticFlag . MANDATORY ) ; }
create a new diagnostic factory .
