How should I copy Strings in Java?

Question

 String s = "hello";

    String backup_of_s = s;

    s = "bye";

At this point, the backup variable still contains the original value "hello" (this is because of String's immutability right?).

But is it really safe to copy Strings with this method (which is of course not safe to copy regular mutable objects), or is better to write this? :

    String s = "hello";

    String backup_of_s = new String(s);

    s = "bye";

In other words, what's the difference (if any) between these two snippets?

Answer 1

Since strings are immutable, both versions are safe. The latter, however, is less efficient (it creates an extra object and in some cases copies the character data).

With this in mind, the first version should be preferred.