Using Reflectors To Dynamically Call Objects

Question

Hi,
I have a Class that has two methods and each method takes two parameters (1st Method Takes Integers / 2nd Takes Double) and returns and Integer. I want to invoke these methods using Java.Reflectors so I could Do dynamic instantiations and method calling.
I have generated an experimental test harness class as given below....
*========================================================*
public static void main(String[] args) {
        try {
            // Getting a Class available in the Pachage to Class Instance
            Class cls = Class.forName("testreflection.ClassMethods");
            // Instance of Current Class
            Main o_Obj = new Main();
            // Get the declared methods in the Class instand "cls"
            Method[] m_Methods = cls.getDeclaredMethods();
            for(int i=0; i<m_Methods.length; i++){
                // Obtain the parameter types of each method
                Type[] typ_MethodParameterTypes = m_Methods.getGenericParameterTypes();
// Int array for Random Integer inputs as Parameters
int[] i_Prameter = new int[typ_MethodParameterTypes.length];
Random r_RandomInt = new Random();
for(int j=0; j<typ_MethodParameterTypes.length;j++){
// Just Display the Input Type
System.out.println(typ_MethodParameterTypes[j].toString());
i_Prameter[j]=r_RandomInt.nextInt();
//Display the Input value to the above type
System.out.println(i_Prameter[j]);
// Trying to invke the 1st Method in the Mehtod array
m_Methods[0].invoke(o_Obj, i_Prameter);
} catch (IllegalArgumentException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvocationTargetException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
//} catch (InstantiationException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} catch (ClassNotFoundException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
*==============================================================*
THen I am getting the following error.... Can any one help me...
int
-1680302169
int
-1149051431
Mar 30, 2011 11:02:53 AM testreflection.Main main
SEVERE: null
java.lang.IllegalArgumentException: object is not an instance of declaring class
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at testreflection.Main.main(Main.java:52)
Edited by: EJP on 30/03/2011 12:17: added the code tags. Please use them.
Edited by: JLearner on Mar 29, 2011 6:18 PM
Edited by: JLearner on Mar 29, 2011 6:20 PM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Answer 1

EJP wrote:
java.lang.IllegalArgumentException: wrong number of argumentsSo you are calling the method with the wrong number of arguments.
The error messages are quite clear, in both cases.Here is the Method that I am Calling in the Class "ClassMethods"
public int getAddition(int i_Number1,int i_Number2){
        int i_Total = i_Number1+i_Number2;
        return i_Total;
    }This method Takes two Integer values and returns an Integer.
I am calling this method using java reflections as below.
// Get the declared methods in the Class instand "cls"
            Method[] m_Methods = cls.getDeclaredMethods();
            for(int i=0; i<m_Methods.length; i++){
                // Obtain the parameter types of each method
                Type[] typ_MethodParameterTypes = m_Methods.getGenericParameterTypes();
// Int array for Random Integer inputs as Parameters
int[] i_Prameter = new int[typ_MethodParameterTypes.length];
Random r_RandomInt = new Random();
for(int j=0; j<typ_MethodParameterTypes.length;j++){
// Just Display the Input Type
System.out.println(typ_MethodParameterTypes[j].toString());
i_Prameter[j]=r_RandomInt.nextInt();
//Display the Input value to the above type
// Currently hold two parameter values
System.out.println(i_Prameter[j]);
// Trying to invke the 1st Method in the Mehtod array
Object obj = cls.newInstance();
m_Methods[0].setAccessible(true);
// invoking with instance of Method own class and parameters (two integer parameters in an array )
m_Methods[0].invoke(obj, i_Prameter);