/**

* Day 32 - Design Patterns: Singleton

*/

public class SingletonExample {

static class Database {

private static Database instance;

private String connectionString;

private Database() {

connectionString = "Connected";

}

static synchronized Database getInstance() {

if (instance == null) {

instance = new Database();

}

return instance;

}

void query(String sql) {

System.out.println("Executing: " + sql);

}

}

public static void main(String[] args) {

Database db1 = Database.getInstance();

Database db2 = Database.getInstance();

System.out.println("Same instance: " + (db1 == db2));

db1.query("SELECT * FROM users");

}

}