In previous article we have covered for loop here we will discuss about the other type of looping statement WHILE. WHILE statement is useful when you want to execute something till a particular condition is true.

Scenario of WHILE loop

Ask user to provide input and wait till user provide the input.

Syntax of WHILE loop

    while (expression) {
         //Do Something
     }

Here while statement will evaluate the expression and check if it is true or not. If true then execute the statement within loop. Once completed execution in loop again check the expression. Perform this activity unless value of expression is not TRUE.

Example Code WHILE loop

class JBT_WhileLoopExample {

	public static void main(String[] args) {

		System.out.println("While For Loop Example");

		boolean bool = true;

		/*
		 * Here while will check the expression. bool value is TRUE so statement
		 * within loop will get executed. Inside loop for first iteration, value of bool is set to
		 * FALSE. Hence in next iteration while loop will check if value of bool
		 * is true or false, now it is FALSE so there will not be next execution
		 * within loop.
		 */
		while (bool) {
			System.out.println("Expression value is TRUE");
			bool = false;
		}

		System.out.println("Expression value is FALSE NOW");
	}

}

Output of above code would be

While For Loop Example
Expression value is TRUE now
Expression value is now FALSE