Java vector<object> class method access

Question

I am trying to use a vector to hold my classes. These classes inherit methods from another class and have their own methods as well. What I am having trouble with is using the vector with objects to call the methods from the class within the object. I thought it would be something like:

public static void vSort(Vector<Object> vector) {
vector[0].generate();
}

with generate being a custom method i created with the student class within the object.

A better example

public class Method {
protected String name;

public void method() {
// some code
}
}
public class Student extends Method {
protected String last;

public void setUp() {
// some code
}
}
public class Main {
public static void main(String[] args) 
{
Vector<Object> vector = new Vector<Object>();
Student stu = new Student(); // pretend this generates something

vector.add(stu);

}

The problem i am running into is there are many classes like student that build on Method. If i cant use Object that is fine with me but i need to access the code within the Method class.

Answer 1

Java doesn't have operator overloads. So the syntax is:

vector.get(0).generate();

However, this won't work at all in your case, because you have a Vector<Object> , and an Object doesn't have a generate method.

[ Tangential note: vector is de facto deprecated; you should probably use ArrayList instead. ]

Answer 2

you should use vector.get(0) to retrieve your object.

Also note, that Object does not declare generate() - so you are going to need to cast or specify your object as thegeneric type.

Answer 3

When you have a Vector<Object> , all the retrieval methods return Object , so you can't call subclass methods unless you explicitly downcast. You should use Vector<YourClass> instead, so that the references you get out of the vector are of type YourClass and you don't have to downcast them.