raja kanak

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Check the above url which gives details about K&B Book available in India.

Good luck

Rate increased from $150 to $200 !!!

A sub-question

int[][] a = {{1,2,}, {3,4}};
After the above code, a is a two dimensional array and a[0], a[1] are one dimensional arrays. Am i right?

If I am right, is the cast necessary in the following line?
int[] b = (int[]) a[1];

Code is from javabeat
import java.util.*; class jb1 { public static void main(String... args) { HashSet<String> hs = new HashSet<String>(); hs.add("scjp"); hs.add("exam"); HashSet<Object> s = new HashSet<Object>(); s.add("check"); s.add(new Integer(5)); // s=hs; //1 } }
In the above code, if i uncomment //1 then it is compilier error. My doubt is, we can add anything into s (set of Objects), then why can't hs? (HashSet is subclass of Object)

Oops. You are right. Now I am clear. Thanks friends.

K&B Chapter 7: Generics and Collections, page number 594 says

public void AddAnimal(List<? super Dog> animals) is essentially, "Hey compiler, please accept any List with a generic type that is of type Dog, or a supertype of Dog. Nothing lower in the inheritance tree can come in , but anything higher than Dog is OK."

Im confused Can any body throw some light on this?

import java.util.*; class GenDemo1 { public static void main(String... args) { List<? super String> l1 = new ArrayList<Object>(); l1.add(new String()); l1.add(new Object()); //1 } }
The above code breaks at //1
Object is super class of String, then why it is not compiling?
[ March 16, 2007: Message edited by: raja kanak ]

Thank you sidd and remi.

public class DemoMethodLocal { public static void main(String... args) { } void doStuff() { final int a; //0 final int b; b=5; class MethodLocalClass { void method() { a=5; //1 System.out.println(a); //2 } } } }
Thanks ShivKumar for your reply. As per your suggestion I modified my code as at //0 final int a; and at //1 included a=5 which gives compile time error "Cannot assign a value to final variable". So i commented //1 and again it complains that "variable a might not have been intialized".

That means we must initialize the variable a before the MethodLocalClass definition.

Again at //0 i removed final modifier, then the compiler error is "local variable a is accessed from within inner class; needs to be declared final"

Conclusion: To access a local variable inside inner class, that variable should be declared final as well as it should be initialized outside the inner class.

Please correct me, if I am wrong.

raja

Originally posted by Jesse Custer:
You are reassigning a final variable. You cannot give 'a' a new value.

I changed //1 as
System.out.println(a);

Still it is problem, "Identifier expected".

class DemoAno { interface Enterface{ void doOneThing(); } }
The code compiles
How can we use this interface & what is use of it?
(I feel it is silly question)

public class DemoMethodLocal { public static void main(String... args) { } void doStuff() { final int a=6; final int b; b=5; class MethodLocalClass { a=6; //1 } } }
The above code shows error at //1 while compiling. I thought since a is declared as final, it can be used inside MethodLocalClass. But what went wrong?

Originally posted by Barry Gaunt:
Did anyone actually receive anything? If no answer, then we'd better close this thread. Nice collection of e-mails here for the spam crawlers to find.

You are right.

class Equ { public static void main(String... args) { Integer i1 = new Integer(5); Integer i2 = new Integer(5); System.out.println(i1==i2); //false Integer i3 = 5; Integer i4 = 5; System.out.println(i3==i4); //true Integer i5 = new Integer(5); Integer i6 = 5; System.out.println(i5==i6); //false int i7 = 5; Integer i8 = new Integer(5); System.out.println(i7==i8); //true } }
Hope the code above will help.

Congrats.