How many String objects are created when the following method is invoked

[Madhan Babu B]

11. public String makingStrings() {
12. String s="Fred";
13. s=s+"47";
14. s=substring(2,5);
15. s=s.toUpperCase();
16. return s.toString();
17. }

[Lorand Komaromi]

12. String s="Fred"; // 1
13. s=s+"47"; // +2
14. s=substring(2,5); // +1
15. s=s.toUpperCase(); // +1
16. return s.toString();
17. }

We can't tell that for sure without knowing the rest of the code, because the two string literals ("Fred" and "47") might have been added to the string pool before this method...

[Madhan Babu B]

thank you!!!

[Lorand Komaromi]

Madhan Babu B wrote:thank you!!!

You're welcome, but I'm not sure about the correctness of my answer. I don't know exactly when the String instances for the literals will be created, when the class is loaded, or when the code is executed, and now I don't have the time to investigate.

I hope someone wil correct me if I was wrong...

[Ulrika Tingle]

Lorand Komaromi wrote:I hope someone wil correct me if I was wrong...

At the Java language level the object associated with a String literal already exists whenever the literal is used. This means that when,

String s="Fred";

is done no object is created. The object associated with "Fred" is defined to already exist. Of course this object must be created at some time but that's an implementation detail.