Explain

[jerry andy]

1.polymorphysm vs encapsulation.
2.inheritence
3.abstract vs inheritance
4.Hash Map
5.Array List
6.Hash Table vs vector

[Jeff Jetton]

Originally posted by jerry andy:
1.polymorphysm vs encapsulation.
2.inheritence
3.abstract vs inheritance
4.Hash Map
5.Array List
6.Hash Table vs vector

Could you give us some idea of what parts you're having trouble with? What questions, specifically, do you have about these concepts?

Regards,

- Jeff

[jerry andy]

Jeff,

I need the definitions and the differences and would be happy if you can give an exaple for the same

[Ryan McGuire]

More specifically, we're always happy to help, but we WON'T do your homework for you from the ground up.

Let's take number 1. Do you know what polymorphism is, even if it's a verbatim reiteration of a definition from the glossary in some text book? Do you know what encapsulation is? Do they work together or are they diametrically opposed (or something inbetween)?

[Jesper de Jong]

First, please do some research yourself.

A place to start with regard to terms like polymorphism, inheritance and encapsulation is for example Wikipedia or Google.

To learn about standard Java classes like HashMap, ArrayList etc. is the Java API documentation.

Also, try doing a search in the forums here, because what you ask has been discussed many times before here; you'll quickly find answers if you search around a bit.

[Justin Fox]

regarding vector, lol, today in "software engineering" vector came up..

and was described as "like an array but more powerfull", because it's

size can change, but was also noted as "less efficient"..

here is the example code i saw...

    
Vector v = new Vector();
Iterator i = new Iterator();
 
while(v.hasNext())
{
   System.out.print(v.next() + " ")
}
 

evidently Iterator is an interface, with .hasNext() and .next()
as abstract methods...

basically my question is, how do vectors work?

and does Iterator only modify vectors?

Justin

[Garrett Rowe]

Actually that code is not entirely correct. It would be:

Vector v = new Vector();
Iterator i = v.iterator();
 
while(i.hasNext())
{   
   System.out.print(i.next() + " ")
}

JF: ...does Iterator only modify vectors?

All implementations of the java.util.Collection interface have an iterator() method which returns an Iterator which can iterate over the elements of that Collection
[ August 31, 2006: Message edited by: Garrett Rowe ]