Dynamic creation of object

Question

Hai
There is a calss Firm like below
public class Firm
public void sayHai()
System.out.println("Hai");
There is a main class like below
public main
public void getObject(String className,Object firmObject)
In this method I am passing Object as a parameter.
I want to accessw sayHai() method of Firm Class by using firmObject
variable.
Actually i am trying like below
Class clsFirm = Class.forName(className);
Object objFirm = clsFirm.newInstance();
objFirm.sayHai(); // Here it is showing error. I am not getting
// How to cast the ObjFirm to actual object.
// Since I know className only.
public static void main(String args[])
          Main doMain = new Main();
Firm doFirm = new doFirm();
          dc.getObject("Firm",doFirm);
Thnks in advance for clarifying my doubt.

Answer 1

There are two approaches. Usually the best one is to predefine an interface which your dynamically loaded are required to implement. Then you can cast the dynamically created object to that interface and call it from there.
public interface DynInterface {
  public void sayHI();
public class Firm implements DynInterface {
  public void sayHi() {
Class cls = Class.forName("Firm");
DynInterface obj = (Dyninterface)cls.newInstance();
obj.sayHi();If you don't have that kind of control over the specs of the dynamically loaded classes they you need to resort to introspecion. In this can use the getMethod() call of Class to get a java.lang.reflect.Method object and use "invoke" on it:
Class cls = Class.forName("Firm");
Method m = cls.getMethod("sayHi", null);
Object obj = cls.newInstance();
m.invoke(obj, null);