Write a java program that emulates a simple calculator: prompts the user to input the left operand and read it into a double variable. prompts the user to input the right operand and read it into a double variable. display a menu which gives the user the choice of the following menu options: 1 -> multiplication 2 -> division 3 -> addition 4 -> subtraction and uses a user validation loop to read their response into a string variable. note: you must repeatedly get the users response until it is exactly one of the characters 1 2 3 4 compute the result of the arithmetic expression, based on the operands and operator provided, and display the entire expression with its result.