And did you perhaps give the variables
values? Like
<code><pre> String hello = "hello";
String java = "java";</pre></code>
If so, then there's really no difference between
<code><pre> System.out.println(hello + java);</pre></code>
and
<code><pre> System.out.println("hello" + "java");</pre></code>
Should there be?
It would be easier to answer your questions if you provided more information about what you're talking about, and why it confuses you.
As for intern(), it's defined in
String.intern().