URLConnection: setIfModifiedSince(long ifmodifiedsince)

import java.net.URL;
import java.net.URLConnection;
import java.util.Date;

public class MainClass {
  public static void main(String[] args) {
    try {
      URLConnection uc = new URL("http://www.demo2s.com").openConnection();
      System.out.println("Will retrieve file if it's been modified since "
          + new Date(uc.getIfModifiedSince()));
      uc.setIfModifiedSince(System.currentTimeMillis());
      System.out.println("Will retrieve file if it's been modified since "
          + new Date(uc.getIfModifiedSince()));
    } catch (Exception e) {
      System.err.println(e);
    }
  }
}