Using Labeled break to Exit Multiple Loops in Java

In Java, the break keyword forcibly exits the current loop, while continue skips the remaining statements of the current iteration and proceeds to the next one.

When loops are nested, a plain break only leaves the innermost loop, which can be surprising during interviews or everyday coding.

Example of exiting a single loop:

package com.sample.core.loop;

public class BreakExample {
    public static void main(String[] args) {
        for (int i = 0; i < 100; i++) {
            System.out.println("第" + i + "次循环");
            if (i == 3) {
                break;
            }
        }
    }
}

If i reaches 3, the loop terminates and no further iterations are executed, producing output up to the third iteration.

Example of nested loops without a label:

package com.sample.core.loop;

public class BreakExample {
    public static void main(String[] args) {
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 5; j++) {
                System.out.println("第" + j + "次内层循环");
                if (j == 1) {
                    break;
                }
            }
            System.out.println("第" + i + "次外层循环");
        }
    }
}

Here, when j equals 1, only the inner loop stops; the outer loop continues, demonstrating that a normal break does not affect outer loops.

Solution with a labeled break to exit all loops:

package com.sample.core.loop;

public class BreakExample {
    public static void main(String[] args) {
        exit_loop:
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 5; j++) {
                System.out.println("第" + j + "次内层循环");
                if (j == 1) {
                    break exit_loop;
                }
            }
            System.out.println("第" + i + "次外层循环");
        }
    }
}

When j reaches 1, the statement break exit_loop; jumps out of both the inner and outer loops, and the program ends after printing the iterations up to that point.

The continue statement can also be used with labels in a similar fashion, though this article does not elaborate on that usage.