Get values of a void method into another method

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Java

public class Demo {

	public static String EvenOrOdd(int n) {
		String s = "";

		if (n % 2 == 0) {
			s = n + " is an Even number";
		} else {
			s = n + " is an Odd number";
		}
		return s;
	}

	public static String isPerfect(int n) {
		int sum = 0;
		String s = "";

		for (int i = 1; i < n; i++) {
			sum += i;

		}
		if (sum == n) {
			s = n + " is a perfect number";
		} else {
			s = n + " is not a perfect number";
		}

		return s;

	}

	public static int gcd(int a, int b) {
		int gcd = 1;
		int k = 2;

		while (k <= a && k <= b) {
			if (a % k == 0 && b % k == 0)
				gcd = k;
			k++;
		}

		return gcd;
	}

	public static int lcm(int a, int b) {
		int x;
		x = (a > b) ? a : b;
		while (true) {
			if (x % a == 0 && x % b == 0)
				return x;
			++x;
		}

	}

	public static String Palindrome(int n) {
		int palindrome = n;
		int reverse = 0;
		String s = "";

		while (palindrome != 0) {
			int remainder = palindrome % 10;
			reverse = reverse * 10 + remainder;
			palindrome = palindrome / 10;
		}

		if (n == reverse) {
			s = n + " is a Palindrome";
		} else {
			s = n + " is not a Palindrome";
		}
		return s;
	}

	public static int Reverse(int n) {
		int reverse = 0;

		while (n != 0) {
			reverse = reverse * 10;
			reverse = reverse + n % 10;
			n = n / 10;
		}

		return reverse;

	}

	public static int SumDigits(int n) {
		int sum = 0;

		while (n != 0) {
			sum += n % 10;
			n /= 10;
		}
		return sum;

	}

	public static String Prime(int n) {
		int j = 2;
		int result = 0;
		String s = "";

		while (j <= n / 2) {
			if (n % j == 0) {
				result = 1;
			}
			j++;
		}
		if (result == 1) {
			return s = n + " is not Prime";
		} else {
			return s = n + " is Prime";
		}

	}

	public static void CallRectangleMethod() {
		int width = (int) (Math.random() * 11);
		int height = (int) (Math.random() * 11);
	}

	// public static int RectangleArea(int width, int height) {
	// return width * height;
	// }

	// public static int RectanglePerimeter(int width, int height) {
	// return 2 * (width * height);
	// }

	public static void main(String[] args) {

	}
}

This is my code.
As you can see there is a method called "CallRectangleMethod" which do not take any parameters. And as you can see the method body in contains 2 randomly generated integers.
So what i am trying to do is i want to assign those two integers that were randomnly generated as parameters into the methods below called "RectangleArea" and "RectanglePerimeter".

What I have tried:

I tried calling the method name.get but unfortunately there exists no built-in methods like that in Java. So i need a little help