Is string interning really useful?

Question

I was having a conversation about strings and various languages a while back, and the topic of string interning came up. Apparently Java and the .NET framework do this auto

Answer 1

String interning is useful when you need to compare strings (1) from a finite set (2) a number of times.

Then the overhead of interning a string is outweighed by the benefit of being able to do a fast == instead of equals().

Doing this can sometimes be faster than using a HashMap, which relies on hashCode() and equals() calls.