break and continue

In Java, break and continue are jump statements used to alter the execution flow of loops. While break terminates the loop immediately, transferring control to the statement following the loop, continue terminates only the current iteration, skipping the remaining loop body statements and jumping to the next iteration check.

Unreachable Statement Errors

The compiler tracks execution paths. If you write code immediately after an unconditional break or continue statement, the compiler flags it with an "unreachable statement" error, preventing compilation:

while (true) {
    break;
    System.out.println("Hello"); // Compile-time error: unreachable statement
}

Execution flow differences: For vs While

When continue is executed:

• In a for loop, control jumps to the update expression (e.g., i++), then to the condition check.
• In a while / do-while loop, control jumps directly to the condition check, skipping any updates. If update operations were placed at the bottom of the loop body, they will be skipped, which can lead to infinite loop traps.

Common Pitfalls

• Unconditional Infinite Loops in While: Placing continue in a while loop before updating the iterator variable, causing the loop to check the same state indefinitely.
• Confusing Break with Return: Using break thinking it exits the method entirely, when it only exits the innermost loop.
• Unreachable Statements: Placing statement logic immediately below unconditional jump statements.

Best Practices

• Use break to exit loops early when search conditions are met.
• Use continue to skip invalid elements at the start of loop bodies, keeping the primary logic clean and unindented.
• Limit the use of nested loops that rely on multiple jumps to keep code easy to read and trace.

Interview-Relevant Information