Anyone to help on reflection ????

Question

Hi People,
Please tell me what's wrong with the following piece of code. All I am trying to do here is, invoke a method of this class through reflection. Need to develop a reusable component.
package TestPro.JSPTest;
import java.lang.reflect.Method;
import java.util.ArrayList;
public class TestClass {
public static Object invokeMethod(String ls_ClassInfo) {
Object obj_Result = null;
try {
if(ls_ClassInfo == null || ls_ClassInfo.trim().length() <= 0)
return null;
int li_MethodNameIndex = 0;
String ls_ClassName = null;
String ls_MethodName = null;
li_MethodNameIndex = (ls_ClassInfo.lastIndexOf(".")+1);
ls_ClassName = ls_ClassInfo.substring(0, li_MethodNameIndex-1);
ls_MethodName = ls_ClassInfo.substring(li_MethodNameIndex);
Class obj_Class = Class.forName(ls_ClassName);
if(obj_Class != null) {
Method obj_Method = obj_Class.getMethod(ls_MethodName, null);
Class[] objClass = obj_Method.getParameterTypes();
obj_Result = obj_Method.invoke(obj_Class, null); // Line throwing the exception
}catch(Exception ex) {
ex.printStackTrace();
return null;
return obj_Result;
public static void main(String args[]) {
Object result = invokeMethod("TestPro.JSPTest.TestClass.setInfo");
public void setInfo() {
System.out.println("Inside the setInfo method of the class................");
Am using jdk 1.3 on Windows 2000.
Everytime I try executing it, I get -
java.lang.IllegalArgumentException: object is not an instance of declaring class
at java.lang.reflect.Method.invoke(Native Method)
at TestPro.JSPTest.TestClass.invokeMethod(TestClass.java:29)
at TestPro.JSPTest.TestClass.main(TestClass.java:39)
Thanks !!!

Answer 1

Well guys,
I found the problem with my code, Its just that the line which threw exception needs to be modified in the following way -
obj_Result = obj_Method.invoke(obj_Class.newInstance(), null);
Initially, I was passing the class object itself, what actually is needed is a new instance of that class.
Hope it helps to the readers.
Cheers,
Rasmeet