chore: just create a few methods in java lib to test

packages/java/src/main/java/io/loganmatic/Main.java

@@ -3,11 +3,75 @@
 public class Main {
     public static void main(String[] args) {
         System.out.println("Hello, World!");
-        System.out.println("Sum: " + Main.add(3, 2));
+        System.out.println("Euler number: " + Main.createEulerNumber(9999));
+        System.out.println("By lib: " + Math.E);
+        System.out.println("Value is: " + (Math.E == Main.createEulerNumber(9999)));
+        System.out.println("Mine has 1 decimal place more than the library one. (: ");
+        System.out.println("Absolute value of -5 is: " + Main.absoluteValue(-5));
+        System.out.println("Square root of 9 is: " + Main.squareRoot(9));
+        System.out.println("Cubic root of -27 is: " + Main.cubicRoot(-27));
     }
 
-    public static int add(int a, int b) {
-        int sum = a + b;
+    public static double power(double base, double exponent) {
+        double result = 1.0;
+        for (int i = 0; i < exponent; i++) {
+            result *= base;
+        }
+        return result;
+    }
+
+    public static double createEulerNumber(int n) {
+        double sum = 0.0;
+
+        for (int k = 0; k < n + 1; k++) {
+            double series = Main.power(1, k) / Main.factorial(k);
+            sum += series;
+        }
         return sum;
     }
+
+    public static double factorial(int valueToCalculate) {
+        // If the value is zero, the factorial is 1
+        if (valueToCalculate == 0) {
+            return 1.0;
+        }
+
+        double result = 1.0;
+        // Iterates over the numbers less than or equal to the value to calculate the factorial
+        for (int i = 1; i <= valueToCalculate; i++) {
+            result *= i;
+        }
+
+        // Returns the result of the factorial
+        return result;
+    }
+
+    public static double absoluteValue(double value) {
+        if (value < 0.0) {
+            return -value;
+        }
+        return value;
+    }
+
+    public static double squareRoot(double valueToCalculate) {
+        double epsilon = 0.00001;  // precision
+        double guess = valueToCalculate;
+
+        while (absoluteValue(guess - valueToCalculate/guess) > epsilon*guess) {
+            guess = (valueToCalculate/guess + guess) / 2.0;
+        }
+
+        return guess;
+    }
+
+    public static double cubicRoot(double valueToCalculate) {
+        double epsilon = 0.00001;  // precision
+        double guess = valueToCalculate;
+
+        while (absoluteValue(guess*guess*guess - valueToCalculate) > epsilon) {
+            guess = guess - (guess*guess*guess - valueToCalculate) / (3.0 * guess * guess);
+        }
+
+        return guess;
+    }
 }