MyClass.java

public class MyClass {
  
    public static void main(String[] args) {
        BigDecimal[] mathArray2 = mathStuff2();
        System.out.println("mathStuff2 func return:");
        for (BigDecimal num: mathArray2) {
            System.out.println(num);
        }  

    public static BigDecimal[] mathStuff2() {
        double area, theta, x, y;
        double r = 1.0; // radius of unit circle

        area = Math.PI * Math.pow(r, 2.0);
        theta = (1.0 / 2) * Math.PI; // 1/2 PI radians
        x = r * Math.cos(theta);
        y = r * Math.sin(theta);

        // convert double variables to BigDecimal inside of new BigDecimal array
        BigDecimal[] ret = new BigDecimal[]{
            new BigDecimal(area),
            new BigDecimal(theta),
            new BigDecimal(x),
            new BigDecimal(y)
        };
        for (BigDecimal val: ret) {
            val.setScale(7, RoundingMode.FLOOR);
        }
        return ret;
    }
}