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K&B chapter 8 Self Test Q 8

Niranjan Deshpande
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Joined: Oct 16, 2005
Posts: 1277

[ November 30, 2005: Message edited by: Barry Gaunt ]

SCJP 1.4 - 95% [ My Story ] - SCWCD 1.4 - 91% [ My Story ]
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Ramakrishna RangaRaoOne AllamOne
Greenhorn

Joined: Nov 28, 2005
Posts: 18
*line 8 seems to be making an anonymous instance as *new Bar() is followed by { }. Thus a ; must follow the second *bracket. Thus code should not compile
-----------------------------------------------


its an anonymous class , but u are not required to end an anonymous class with a semicolumn . the reason why u might thoght lik ethat is : it is afterall like a statement . But here the statement is anyways there . U are endng that statement with a ; . So must be ok ..
james edwin
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Joined: Nov 22, 2001
Posts: 393
Answer C is correct .Foo constructtor will be called first,then Bar constructor and then makeBar Method


Regards,
James
Gyanesh Sharma
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Joined: Nov 27, 2005
Posts: 47
The assumption that the definition of an anonymous class must end with ; is correct only if the statement was an asignment statement. However in your code sample, an instance of the anonymous class is created and one of the method of the class is called in the same statement. So the ; goes in the end.
For example
a = new X();
a.doStuff();
can be written as new X().doStuff; but not as new X();.doStuff;
Barry Gaunt
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Joined: Aug 03, 2002
Posts: 7729
The class Foo compiles and runs and prints out "foobarhi". So any assumption about a colon being necessary after the new Bar{}() is incorrect. That's it. It just creates a non-referenced object of an anonymous subclass of Bar. The code just happens to call the method doStuff(), inherited from Bar, for the side-effect of printing "hi". That's where the semicolon belongs, after the method call, and there it is. Because the object has no reference to it, it is immediately eligible for garbage collection.
[ December 01, 2005: Message edited by: Barry Gaunt ]

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rajendra naidu kumar
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Joined: Dec 06, 2005
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DEAR RANCHERS,
PLZ HELP IAM PREPARING FOR A SCJP1.4;
IS IT SUFFICIENT K&B BOOK.
Leoo yu
Greenhorn

Joined: Nov 01, 2005
Posts: 13

Result : foobarHIT
I hope this can help you .
Leoo yu


[Deleted]
Niranjan Deshpande
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Joined: Oct 16, 2005
Posts: 1277
I agree with you all....
but my question was what is the need to put { } after
Bar() ???

(new Bar() {}).go();

i know that

new Bar().go()

is as good as

Bar b=new Bar();
b.go()

but we never use (new Bar(){}).go( );
If you remove the {} the code compiles and runs fine

So the {} make it an unreferenecef anonymous class ???
then, whats the difference between
new Bar().go(); and
(new Bar() {}).go();

please help out
thanks in advance
Jan Valenta
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Joined: Nov 30, 2005
Posts: 32
Originally posted by Niranjan Deshpande:

So the {} make it an unreferenecef anonymous class ???
then, whats the difference between
new Bar().go(); and
(new Bar() {}).go();


try:



this is actualy overriding the go() method. So "(new Bar() {}).go();" is probably extending Bar but not making any overriding.


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subject: K&B chapter 8 Self Test Q 8
 
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