Question

I have read in a Java book that says:

Because a String is immutable, using StringBuffer is more efficient.

I understand that String instances are immutable.

I also understand that StringBuffer makes processing Strings more effcient than normal.

But the thing I can’t work out is what connects these two concepts, i.e. how does String being immutable help StringBuffer?

Thanks 🙂

Answer 1

But the thing I can’t work out is what connects these two concepts, i.e. how does String being immutable help StringBuffer?

It doesn’t. I think that you are simply misinterpreting the sentence that you quoted.

“Because a String is immutable, using StringBuffer is more efficient.”

It is saying that StringBuffer is a relative more efficient option (for certain tasks). In other words: “Because a String is immutable, using StringBuffer is more efficient [than using String for certain tasks].”.

It is NOT saying that StringBuffer is faster in absolute terms than it would be if String wasn’t immutable. Certainly, that’s not how I read the quote … and it is not a true statement either.