Java immutable strings confusion

Question

If Strings are immutable in Java, then how can we write as:

String s = new String();
s = s + \"abc\";

Answer 1

   String s = new String();  

Creates a new, immutable, empty string, variable "s" references it.

   s = s+"abc";              

Creates a new, immutable, string; the concatenation of the empty string and "abc", variable "s" now references this new object.