the program has to be written in java

Write a program that reads the lengths of the three sides of a triangle, checks whether the input is valid, and computes the perimeter and the area of the triangle if the input is valid. Three numbers are the lengths of the three sides of a valid triangle if and only if they are all positive and the sum of every two is greater than the remaining one. You can use the following formula (known as Heron's formula) to calculate the area of a triangle: Of a triangle whose three sides have lengths a, b and c, the area is squareroot s(s - a) (s - b) (s - c) where s = a + b + c/2, i.e. half of the triangle's perimeter