Java PushbackReader.unread(char[] cbuf, int off, int len)

public void unread(char[] cbuf,  int off,  int len)  throws IOException

//  ww w .  jav a2s  .  c  o  m

import java.io.*;

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);
         }
         char cbuf[] = {'w', 'o', 'r', 'l', 'd'};

         pr.unread(cbuf, 1, 4);

         for (int i = 0; i < 4; i++) {
            char c = (char) pr.read();
            System.out.println(c);
         }

         pr.close();

      } catch (IOException ex) {
         ex.printStackTrace();
      }
   }
}