String Pool behavior

Question

I read this Questions about Java's String pool and understand the basic concept of string pool but still don\'t understand the behavior.

First: it works if you

Answer 1

I think what happens here is: 1. for String s1 = "a" + "bc"; String s2 = "ab" + "c"; Java compiler is smart enough to know that the literal value of s1 and s2 are the same, so the compiler points them to the same literal value in the string pool

1. for s1 += "d";
   s2 += "d";

there is no way the compiler know if s1 and s2 would end up being the same value, At runtime, unless you call String.intern(), jvm won't check the string literal pool to see if the value is already there.