Read time from internet time server - working java code

Read time from internet time server - working java code

import java.io.*;
import java.net.*;
import java.util.*;

/**
 * This program makes a socket connection to the atomic clock in Boulder,
 * Colorado, and prints the time that the server sends.
 */
public class Time_Server_Socket_Test_Java {
    public static void main(String[] args) {
        try {
            Socket s = new Socket("time-A.timefreq.bldrdoc.gov", 13);
            try {
                InputStream inStream = s.getInputStream();
                Scanner in = new Scanner(inStream);

                while (in.hasNextLine()) {
                    String line = in.nextLine();
                    System.out.println(line);
                }
            } finally {
                s.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

iterate through map hashmap linkedhashmap in java

How to iterate through Map.. MashMap, LinkedHashMap ...  in Java
Method 1 : If you're only interested in the keys, you can iterate through the keySet() of the map:

Map map = ...;

for (String key : map.keySet()) {
    // ...
}

Method 2 :

java escape text in regular expression

Java's a built-in way to escape arbitrary text so that it can be included in a regular expression-
For example, users enter "$5", we can match that exactly rather than a "5" after the end of input.


Just do this : to escape text in regex

Pattern.quote("$5");

use of @override annotation in java - why ?

The @override annotation  is most useful as a compile-time reminder that the intention of the method is to override a parent method. See this example:

import java.util.HashSet;
import java.util.Set;
/**
 * Override_Annotation_Usage_Example, from  Effective Java
 */