public class test{
 public static void main(String[] args){
  try{
   String s = "";
   while(!s.equals("q")){
    System.out.print("input:");
    DataInputStream in = new DataInputStream(new BufferedInputStream(System.in));
    s = in.readLine();
    System.out.println("your input is :"+s);
    String check = "^([a-z0-9A-Z]+[-|\\._]?)+[a-z0-9A-Z]@([a-z0-9A-Z]+(-[a-z0-9A-Z]+)?\\.)+[a-zA-Z]{2,}$";
    Pattern regex = Pattern.compile(check);
                Matcher matcher = regex.matcher(s);
                boolean isMatched = matcher.matches();
                if(isMatched){
                 System.out.println("it's a email");
             }else{
              System.out.println("it's not a email");
             } 
    
   }
        }catch(Exception e){
         System.out.println("error"+e.getMessage());
     }
 }         
}