Invoking Derived Class Method

Question

Hi pls go through the below code, can any one give me solution how to access the Derived class method in this Point.
Note: In the below code , only in runtime we will come to know which Derived class method is going to invoke(So in runtime we will get Derived class name in the form of String). So Iam trying to Use Class.forName("Clas name") to create the instance of the Derived class and then type casting to base class.
Why iam casting to base class is , since only in the run time we are geting the Derived class name.
Result : iam geting the compiletime error says that no valid method fond in Mybase though it contains the reference of derived.
abstract class MyBase
public void display(int i)
System.out.println(" Base class Method");
class MyDerived extends MyBase
public void display(String str)
System.out.println("Derived class Mthode");
class MyMain
public static void main(String arg[])
String DrivObj=arg[0];
MyBase baseObj=(MyBase) Class.forName("DrivObj").newInstance();
baseObj.display("SomeString"); }
}

Answer 1

The problem is, can not have subclass reference bcoz
iam geting the subclass name only in the runtime and
one more thing is cant touch my base and subclass to
do changes as u said Your design is then definately very bad.
, is there any other way to do
it.Yes, you can use reflection to invoke the method.
Kaj