Few Java snippets

String a = String.valueOf(2);   //integer to numeric string
int i = Integer.parseInt(a); //numeric string to an int

String to Date

SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" );
Date date = format.parse( myString );

Creating JSON data in Java

import org.json.JSONObject;
...
...
JSONObject json = new JSONObject();
json.put("city", "Mumbai");
json.put("country", "India");
...
String output = json.toString();
...

Java Singleton example

public class SimpleSingleton {
    private static SimpleSingleton singleInstance =  new SimpleSingleton();
 
    //Marking default constructor private
    //to avoid direct instantiation.
    private SimpleSingleton() {
    }
 
    //Get instance for class SimpleSingleton
    public static SimpleSingleton getInstance() {
 
        return singleInstance;
    }
}

Send HTTP request & fetching data using Java

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
 
public class Main {
    public static void main(String[] args)  {
        try {
            URL my_url = new URL("http://www.xyz.com/");
            BufferedReader br = new BufferedReader(new InputStreamReader(my_url.openStream()));
            String strTemp = "";
            while(null != (strTemp = br.readLine())){
            System.out.println(strTemp);
        }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

Convert Array to Map in Java

import java.util.Map;
import org.apache.commons.lang.ArrayUtils;
 
public class Main {
 
  public static void main(String[] args) {
    String[][] countries = { { "United States", "New York" }, { "United Kingdom", "London" },
        { "Netherland", "Amsterdam" }, { "Japan", "Tokyo" }, { "France", "Paris" } };
 
    Map countryCapitals = ArrayUtils.toMap(countries);
 
    System.out.println("Capital of Japan is " + countryCapitals.get("Japan"));
    System.out.println("Capital of France is " + countryCapitals.get("France"));
  }
}

HTTP Proxy setting in Java

System.getProperties().put("http.proxyHost", "someProxyURL");
System.getProperties().put("http.proxyPort", "someProxyPort");
System.getProperties().put("http.proxyUser", "someUserName");
System.getProperties().put("http.proxyPassword", "somePassword");