The gravitational attraction between any two objects in the universe is given by the following formula:

Force of Gravity = (G * m * n) / r²

Where m and n are masses of the objects in kilograms, r is the distance between them in meters, and G is the gravitational constant 6.67 * 10^-11

java program that prompts the user to enter m, n, and r, then calculates and prints the Force of Gravity if the user inputs are valid.

Use two-way selection (if-else) with logical operator (AND / OR) structure to validate the user inputs. Display an error message if the inputs are invalid.

Basically, if all three values (m, n, and r) are greater than 0, they are valid. If one of them is less than or equal to 0, they are not valid.