break Keyword in Java with Examples

The break keyword is used to prematurely exit a for, while, or do while loop or to mark the end of a case block in a switch statement.

Let's discuss how to use break keyword in for loop, while loop and switch statement with examples.

1. Using a break keyword to Exit a for Loop

By using a break, you can force immediate termination of a loop, bypassing the conditional expression and any remaining code in the body of the loop. When a break statement is encountered inside a loop, the loop is terminated and program control resumes at the next statement following the loop.

Here is a simple example:

package net.javaguides.corejava.controlstatements.loops;

public class BreakWithForLoop {
    public static void main(String args[]) {
        for (int i = 0; i < 100; i++) {
            if (i == 10)
                break; // terminate loop if i is 10
            System.out.println("i: " + i);
        }
        System.out.println("Loop complete.");
    }
}

Output:

i: 0
i: 1
i: 2
i: 3
i: 4
i: 5
i: 6
i: 7
i: 8
i: 9
Loop complete.

As we can see, although the for loop is designed to run from 0 to 99, the break statement causes it to terminate early, when i equals 10.

2. Using break to Exit a while Loop

package net.javaguides.corejava.controlstatements.loops;

public class BreakWithWhileLoop {
    public static void main(String args[]) {
        int i = 0;
        while (i < 100) {
            if (i == 10)
                break; // terminate loop if i is 10
            System.out.println("i: " + i);
            i++;
        }
        System.out.println("Loop complete.");
    }
}

Output:

i: 0
i: 1
i: 2
i: 3
i: 4
i: 5
i: 6
i: 7
i: 8
i: 9
Loop complete.

3. Using break with Nested Loops

When break keyword used inside a set of nested loops, the break statement will only break out of the innermost loop. 

For example:

package net.javaguides.corejava.controlstatements.loops;

public class BreakWithNestedLoops {
    public static void main(String args[]) {
        for (int i = 0; i < 3; i++) {
            System.out.print("Pass " + i + ": ");
            for (int j = 0; j < 100; j++) {
                if (j == 10)
                    break; // terminate loop if j is 10
                System.out.print(j + " ");
            }
            System.out.println();
        }
        System.out.println("Loops complete.");
    }
}

Output:

Pass 0: 0 1 2 3 4 5 6 7 8 9 
Pass 1: 0 1 2 3 4 5 6 7 8 9 
Pass 2: 0 1 2 3 4 5 6 7 8 9 
Loops complete.

Using break with a switch case Statement

public class BreakSwitchCaseExample {

    public static void main(String args[]) {
        int num = 2;

        switch (num) {
            case 1:
                System.out.println("Case 1 ");
                break;
            case 2:
                System.out.println("Case 2 ");
                break;
            case 3:
                System.out.println("Case 3 ");
                break;
            default:
                System.out.println("Default ");
        }
    }
}

Output:

Case 2