Java PushbackReader.mark(int readAheadLimit)

public void mark(int readAheadLimit)  throws IOException

import java.io.*;
//from w w  w.  j  a  va  2 s  .  co  m
public class Main {
   
   public static void main(String[] args) {
      
      String s = "from java2s.com";

      StringReader sr = new StringReader(s);

      PushbackReader pr = new PushbackReader(sr, 20);
      
      try {
         for (int i = 0; i < 5; i++) {
            char c = (char) pr.read();
            System.out.println(c);
         }
         pr.mark(5);
         pr.close();
         
      } catch (IOException ex) {
         ex.printStackTrace();
      }
   }
}