String Pooling...!!!

[Vishal K Patel]

Here is one question I found in one book....!!!

Q .Consider the following lines of code:
String s1 = "Whatever";
String s2 = new String("Whatever");
String s3 = new String ("Who");
Which of the following statements is true? (Choose all that apply.)

A. The compiler will create two strings Whatever and Who and put them in the pool, and
there will be a string Whatever and Who created at runtime.

B. The compiler will create two strings Whatever and Who and put them in the pool, and
there will be no string created at runtime.

C. The compiler will create two copies of Whatever and one copy of Who and put them in
the pool, and there will be strings Whatever and Who created at runtime.

D. The compiler will create one copy of Whatever and put it in the pool, and there will be
strings Whatever and Who created at runtime.

E. The compiler will create a string Whatever and put it in the pool, and there will be a
string Who created at runtime.

Ans : According to me " D " is the answer.

but they are saying that the answer is " A ".
and justifying in this way....

The compiler creates a string when it sees a string literal, but it does not create duplicates. The
statement with the new operator will be executed at runtime, and the string will be created even if
an identical string was created by the compiler.

Can anybody explain their justification?

[ March 22, 2007: Message edited by: Vishal K Patel ]
[ March 22, 2007: Message edited by: Vishal K Patel ]

[jianfeng shi]

The compiler will create strings when saw different strings and put them in the pool.There will be a string version in pools later.And put the in the pool.
In this section there use new... so you tell the complier "I want a new string one not the same version in pool. And this obj will put in the stack.

[Vishal K Patel]

But here they are saying that "Whatever" and "who" both are created in the pool...?
Is it correct?
We are using new to create them....!!!

Have you read the options [A]and [D]?
What should be the correct?

[Chris Stann]

quote:

Q .Consider the following lines of code:
String s1 = "Whatever";
String s2 = new String("Whatever");
String s3 = new String ("Who");
Which of the following statements is true? (Choose all that apply.)

A. The compiler will create two strings Whatever and Who and put them in the pool, and
there will be a string Whatever and Who created at runtime.

B. The compiler will create two strings Whatever and Who and put them in the pool, and
there will be no string created at runtime.

C. The compiler will create two copies of Whatever and one copy of Who and put them in
the pool, and there will be strings Whatever and Who created at runtime.

D. The compiler will create one copy of Whatever and put it in the pool, and there will be
strings Whatever and Who created at runtime.

E. The compiler will create a string Whatever and put it in the pool, and there will be a
string Who created at runtime.

The compiler creates a string when it sees a string literal, but it does not create duplicates. I see 3 string literals. Two are duplicates. Compiler creates 2 strings - "Whatever" and "Who"

The statement with the new operator will be executed at runtime, and the string will be created even if an identical string was created by the compiler. I see 2 new operators. At run time 2 strings will be created - "Whatever" and "Who".

It seems to me that this explains why answer "A" is correct.

[fred rosenberger]

well, i think 'd' is correct. It may not be COMPLETE, but i don't see anything untrue about what it is saying.

A, however is confusing. "there will be a string Whatever and Who created at runtime".

that "a string" sounds like there will be only one single string created.

so i don't know what the right answer is.

[gianni ipez]

Sometimes I find mocks that are misleading.
they attempt to be tricky and force you to reason, but they only confuse your mind.

[Chris Stann]

Out of what book did this question come? The K&B book is supposed to cover "everything you need to know" for the exam, and I do not recall covering this type of question - it does not drill down to this level of detail of String object and pool creation.

[Bert Bates]

This discussion is a tiny bit outside the scope of the exam.

[Chris Stann]

Thanks, Bert!