Practical Implementation of Singleton Class

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Practical Implementation of Singleton Class



 

class Singleton

{

    public static void main(String args[])

    {

        Thread t = new Thread(new Runnable(){

            public void run()

            {

                DatabaseConnection obj = DatabaseConnection.getInstance();

            }

        });

        Thread t1 = new Thread(new Runnable(){

            public void run()

            {

                DatabaseConnection obj = DatabaseConnection.getInstance();

            }

        });

        t.start();

        t1.start();

    }

}

class DatabaseConnection{

    private static DatabaseConnection instance;

    private DatabaseConnection()

    {

        // private constructor to prevent external instatiation

        System.out.println("Instance will be created.");

    }

    public static synchronized DatabaseConnection getInstance()

    {

        if(instance == null)

        {

            instance = new DatabaseConnection();

        }

        return instance;

    }

}

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