How Does the do-while Loop Differ from the while Loop in Java?
How Does the do-while Loop Differ from the while Loop in Java?
Ask by Ashutosh Patel
Updated 28 Mar 2025
The Java programming language contains both while and do-while loop syntax to allow a code segment to be executed based on specified conditions. The main distinction exists in the way these loops check the condition.
A while loop first checks the condition before starting its loop body execution. At the beginning, when the condition turns out to be false, the loop body fails to perform any execution. The unknown number of iterations only depends on this specific condition, so this loop functionality is useful.
In contrast, the do-while loop executes the loop body at least once, regardless of the condition. After the first pass through the loop, the condition will be evaluated and checked. The do-while loop provides a valuable functionality for running a block of code once before evaluating the condition, since it checks after the first execution.
Example: Difference Between while and do-while
The while loop does not activate because count has reached the value of 5. The executable code block in a do-while loop executes once before the condition evaluation enables at least one execution of the print statement.
The while loop functions best when program execution depends completely on a validating condition, while the do-while loop performs at least one statement execution before conducting validation tests.