Java Programming - Java.lang Class - Discussion

Discussion Forum : Java.lang Class - Finding the output (Q.No. 1)
1.
What will be the output of the program?
String x = new String("xyz");
String y = "abc";
x = x + y;
How many String objects have been created?
2
3
4
5
Answer: Option
Explanation:

Line 1 creates two, one referred to by x and the lost String "xyz". Line 2 creates one (for a total of three). Line 3 creates one more (for a total of four), the concatenated String referred to by x with a value of "xyzabc".

Discussion:
31 comments Page 2 of 4.

Deepak said:   1 decade ago
"abc", "xyz", x, y and "xyzabc" total 5 objects will be created.

xyz will be lost as x now points to new concatenated string. Hence
5-1 = 4 objects.

Md Zakir said:   1 decade ago
There are only 3 objects will be created because.

In First line,

String x = new String("xyz");

"xyz" an object is created in memory which is referenced by x(reference variable).if u get the hasCode() of "Hello" and x both will be same because x is referenced to "xyz"

String y = "abc";

This line create one object "abc" which is referenced by y;

And finally when,
x = x + y;

A new object is created "xyzabc" which is referenced by x.
String class is an Immutable string so it is not changed a new object is created when concatenation is performed and is referenced by x.

Dasoju said:   1 decade ago
Please summarize somebody, can we fix the answer as 3 objects.

Please conclude the discussion with proper explanation.

Thanks.

M pradeep said:   1 decade ago
Can anyone show the proof that how 4 objects are getting created. I mean is there any way to show to someone on the machine by executing the program.

Gaurav Kumar said:   1 decade ago
Can anyone tell me that why line one creates two object. It should create only one object and this answer is wrong.

Jinesh said:   1 decade ago
I believe "xyz" is a string literal and not string object. So line creates only one object. Also, as stated, literal "xyz" is not lost as its sitting in the stringpool. "xyz" is not a string object.

Line 2 is also creating another string literal in string pool and its not string object.

Line 3 (concatenation) creates another string object.

So in all - 2 objects - one at line 1 and another at line 3.

Anandi Shewale said:   1 decade ago
I agree that Line 1 creates 2 object, and 2nd line 1 object but how 4th object is created?

Xyzabc said:   1 decade ago
@Anandi.

String is immutable so new object xyzabc is created.

Harsha rao said:   1 decade ago
Proof is:

String x = "xyz";

x == "xyz" false.

Because x referring ingredients of xyz but not to xyz.

And "xyz" is another.

1 line>2.
2> line 1.
3>line 1.

Richa said:   1 decade ago
String x = new String ("xyz"); /* one object created here "xyz", note: x is a reference variable only */.

String y = "abc"; /* one object created here "abc", note: y is a reference variable only */.

X = x + y; /* one object created here "xyzabc" referenced by existing x variable */.

So, total 3 objects are only created. Do not get confuse between Objects and reference variables.


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