hello,  my trouble is exampled in the code. Please take a look and give
me some threads. thanks.

TestArray.java
//-----------------------------------------------------
import java.util.Vector;
public class TestArray {
    public static void main(String[] agrs) {

               // I only want to get an Array from the Vector v
               Vector v = SomeClass.getVector();

        // I can make sure the object type is correct
        // I have checked every object in v is instanceof SomeClass
               // [method1] and [method2] both throw
ClassCastException
        SomeClass[] sc1 = (SomeClass[]) v.toArray(); // [method 1]
        SomeClass[] sc2 = (SomeClass[]) toArray2(v); // [method 2]

               // I have to code like this, and no exception any more.
Why?
        SomeClass[] sc3 = new EmMessage[v.size()]; // [method 3]
        for (int i = 0; i < v.size(); i++) {
            sc4[i] = (SomeClass) v.elementAt(i);
        }
    }

    public static Object[] toArray2(Vector vector) {
        if (vector == null) {
            return new Object[0];
        }
        Object[] obs = new Object[vector.size()];
        for (int i = 0; i < obs.length; i++) {
            obs[i] = vector.elementAt(i);
        }
        return obs;
    }

}