"loop:" in Java code. What is this, and why does it compile?
It is not a keyword
it is a label
.
Usage:
label1:
for (; ; ) {
label2:
for (; ; ) {
if (condition1) {
// break outer loop
break label1;
}
if (condition2) {
// break inner loop
break label2;
}
if (condition3) {
// break inner loop
break;
}
}
}
Documentation.
The question is answered, but as a side note:
I have heard of interview questions a la "Why is this Java code valid?" (stripped the simpler example; here's the meaner one, thx Tim Büthe):
url: http://www.myserver.com/myfile.mp3
downLoad(url);
Would you all know what this code is (apart from awful)?
Solution: two labels, url
and http
, a comment www.myserver.com/myfile.mp3
and a method call with a parameter that has the same name (url
) as the label. Yup, this compiles (if you define the method call and the local variable elsewhere).
As other posters have said, it is a label, not a keyword. Using labels allows you to do things like:
outer: for(;;) {
inner: for(;;) {
break outer;
}
}
This allows for breaking of the outer loop.
Link to documentation.