for
A loop with a counter, or iteration over every element of an array or collection (for-each).
Available since: Java 1.0
Syntax
for (init; condition; update) { … } / for (Type item : collection) { … }Examples
A classic loop with a counter:
void main() {
for (int i = 1; i <= 3; i++) {
IO.println("step " + i);
}
}Output:
step 1
step 2
step 3for-each — iteration without an index:
void main() {
List<String> names = List.of("Anna", "Oleg");
for (String name : names) {
IO.println("Hi, " + name);
}
int sum = 0;
for (int n : new int[] {4, 5, 6}) {
sum += n;
}
IO.println(sum);
}Output:
Hi, Anna
Hi, Oleg
15Notes
for-each gives no index, and you cannot remove elements from the collection inside it — you get ConcurrentModificationException. Use removeIf() or an iterator to remove. The counter variable i exists only inside the loop.
See also
- while / do-while — Repeats a block while a condition is true; do-while runs it at least once.
- break / continue — break exits a loop, continue jumps to the next iteration; a label lets you leave a nested loop.
- array.length — The length of an array — the number of elements. A field, not a method: no parentheses.
Related recipes
In the tutorial
- Loops — Loops in Java: while, do-while, for and for-each over an array.