ContactUs :

Please send your Questions & Answers or Feedback to ""

What is Singleton class ?

Singleton is a class which has only one instance in whole application and provides a getInstance() method to access the singleton instance.


For example, you can use it to create a connection pool. It’s not wise to create a new connection every time a program needs to write something to a database; instead, a connection or a set of connections that are already a pool can be instantiated using the Singleton pattern.



import java.util.Properties;


public class DBInfo {

    static private DBInfo _instance = null;

    static public String port = null;

    static public String database = null;

    static public String ip = null;

    static public String user = null;

    static public String pass = null;

    static public String jdbc = null;

    static public String driver = null;

    static public String instance = null;


    protected DBInfo(){


        InputStream file = new FileInputStream(new File("")) ;

        Properties props = new Properties();


        port = props.getProperty("PORT");

        ip = props.getProperty("IP");

        database = props.getProperty("DATABASE");

        user = props.getProperty("USER");

        pass = props.getProperty("PASS");

        jdbc = props.getProperty("JDBC");

        driver = props.getProperty("DRIVERNAME");

        instance = props.getProperty("INSTANCE");


    catch(Exception e){

        System.out.println("error" + e);




    static public DBInfo instance(){

        if (_instance == null) {

            _instance = new DBInfo();


        return _instance;



Related Posts Plugin for WordPress, Blogger...
Flag Counter