If we ever want to exit a loop before it finishes all its iterations or want to skip one of the iterations, we can use the break and continue keywords.

The break keyword is used to exit, or break, a loop. Once break is executed, the loop will stop iterating. For example:

for (int i = 0; i < 10; i++) {
  System.out.println(i);
  if (i == 4) {
    break;
  }
}

Even though the loop was set to iterate until the condition i < 10 is false, the above code will output the following because we used break:

0
1
2
3
4

The continue keyword can be placed inside of a loop if we want to skip an iteration. If continue is executed, the current loop iteration will immediately end, and the next iteration will begin. We can use the continue keyword to skip any even valued iteration:

int[] numbers = {1, 2, 3, 4, 5};

for (int i = 0; i < numbers.length; i++) {
  if (numbers[i] % 2 == 0) {
    continue;
  }
  System.out.println(numbers[i]);
}

This program would output the following:

1
3
5

In this case, if a number is even, we hit a continue statement, which skips the rest of that iteration, so the print statement is skipped. As a result, we only see odd numbers print.

Keep Reading: AP Computer Science A Students

Loops can exist all throughout our code - including inside a method. If the return keyword was executed inside a loop contained in a method, then the loop iteration would be stopped and the method/constructor would be exited.

For example, we have a method called checkForJacket() that takes in an array of Strings. If any of the elements are equivalent to the String value "jacket", the method will return true:

public static boolean checkForJacket(String[] lst) {
  for (int i = 0; i < lst.length; i++) {
    System.out.println(lst[i]);
    if (lst[i] == "jacket") {
      return true;
    }
  }
  return false;
} 

public static void main(String[] args) {
  String[] suitcase = {"shirt", "jacket", "pants", "socks"};   
  System.out.println(checkForJacket(suitcase));
}

As soon as an element equals "jacket", return true; is executed. This causes the loop to stop and the compiler to exit checkForJacket(). Running this code would output the following:

shirt
jacket
true