Help required on some interview questions!!

[amit bose]

Hi All,

Recently I was asked the following questions for an interview.
I would appreciate if the guru's here help me out with the answers:

1) What's the difference b/w
String s="abc";
//and
String s= new String("abc");

2) What are the implicit variables in a JSP ( that are readily available for use)

3) What is the difference between Container and Server?

4) Sometimes we do have to declare a class abstract when there aren't any abstract methods in it, Why?
Any particular scenario of importance ?

5) Why do abstract class have constructors when we cannot instantiate them?

6) How can we sort an arraylist using comparator?
Code snippet will really help.


Best Regards,
Amit

[Ernest Friedman-Hill]

None of these are performance questions; I'll move this topic to Java in General (Beginner), although personally, I'd prefer to see these asked one at a time, and I'd want to see you post your answers, so other people could critique them.