What is wrong with my java codes?

[phpuser123]

I just happened to read abt vectors in java..For some practice,I implemented this small script where I Store objects in a vector..Then,I want to invoke the methods of the corresponding objects.My problem is that in this line

System.out.println(vc.elementAt(i).test3());

the test3() method of my object is being underlined..I know I am retrieving an abject from vc.elementAt(i),then why is the method test3() being underlined??

import java.util.*;
public class MITlab2 {
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         test_vector1();
    }
 
 
    public static void test_vector1(){
        test_class vm=new test_class();
        Vector vc=new Vector();
        vc.add(vm);vc.add(vm);vc.add(vm);
        System.out.println(vc.size());
        for (int i=0;i<vc.size();i++){
            System.out.println(vc.elementAt(i).test3());
        }
 
    }
 
}
class test_class{
    public String vim="testing";
    public boolean test3(){
        return true;
    }
}
 

[Dheeraj Joshi]

You code in line 19 should be changed.

((test_class) vc.elementAt(i)).test3()
 

This is because test3 function is the member of test_class and you are using it in MITLab2 class.

Regards
Dheeraj Joshi

[konapalligopi]

There The return type is Object so u need to do implicit conversion buddy

[phpuser123]

Thanks dheerajjoshim and konapalligopi,The code worked...
But I hava a slight problem understanding this...

I used vm.test3() and it worked fine but then why didn't it work on vc.elementAt(i).test3()??

Why does it work with vm.test3() when vm also is an object....Why i don't have to do this conversion??A bit confused here...

[jkmyoung]

You've explicitly declared vm as a test_class object.
vc.elementAt(i) is just an object, needs to be explicitly cast.

You could always set your vector to only hold test_class objects (assuming you're using java 1.5 or higher.

eg Vector <test_class> vc=new Vector<test_class>();