public enum types {
Oracle,MySQL
}

public class Iconnection {
types contype;
public String username;
public String password;
public String driver;
public String DB_URL;
public Connection connection;
public Statement statement;
public Iconnection(types contype)
{
    this.contype=contype;

}
public types gettype()
{
    return contype;
}
public void settype(types contype)
{
    this.contype=contype;
}

protected void construct(String driver,String username,String password)
{
        try {
        Class.forName(driver);
    } catch (ClassNotFoundException ex) {
        Logger.getLogger(ORcon.class.getName()).log(Level.SEVERE, null, ex);
        System.out.println("can't connection1");
    }
    try {
        this.connection=DriverManager.getConnection(driver, username, password);
    } catch (SQLException ex) {
        Logger.getLogger(ORcon.class.getName()).log(Level.SEVERE, null, ex);
        System.out.println("can't connection2");
    }
    try {
        this.statement=this.connection.createStatement();
    } catch (SQLException ex) {
        Logger.getLogger(ORcon.class.getName()).log(Level.SEVERE, null, ex);
        System.out.println("can't connection3");
    }

}
}

public class ORcon extends Iconnection{
private static Iconnection instance = new Iconnection(types.Oracle);
ORcon()
{
    super(types.Oracle);
    this.username = "root";
    this.password="root";
    this.driver="oracle.jdbc.driver.OracleDriver";
    this.DB_URL="jdbc:oracle:thin:@localhost:1521:mydb";
    super.construct(this.driver,this.username,this.password);
}
public static Iconnection getinstance()
{
    if(instance==null)
        instance=new ORcon();
    return instance;
}
}

public class MYScon extends Iconnection{
private static Iconnection instance = new Iconnection(types.Oracle);
MYScon()
{
    super(types.MySQL);
    this.username = "root";
    this.password="root";
    this.driver="com.mysql.jdbc.Driver";
    this.DB_URL="jdbc:mysql://localhost:3306/mydb";
    super.construct(this.driver,this.username,this.password);
}
public static Iconnection getinstance()
{
    if(instance==null)
        instance=new MYScon();
    return instance;
}
}

public class ConnectionFactory {
public static Iconnection creatconnectoin(types cotype)
{
    Iconnection Icon=null;
    switch (cotype)
    {
        case Oracle:
            Icon=new ORcon();
            break;

        case MySQL:
            Icon=new MYScon();
            break;
    }
    return Icon;
}
}