Mathematical rounding

There are several mathematical rounding methods in Java.

Math.floor(val): Returns the largest (closest to positive infinity) double value that is less than or equal to the argument and is equal to a mathematical integer.

Math.ceil(val): Returns the smallest (closest to negative infinity) double value that is greater than or equal to the argument and is equal to a mathematical integer.

Math.round(val): Returns the closest long to the argument, with ties rounding to positive infinity.

import java.util.Scanner;

class Rounding {
	private static double roundDouble(double value, int decimalPoints) {
		double d = Math.pow(10, decimalPoints);
		return Math.round(value * d) / d;
	 }
	public static void main(String[] arg) {
		double val = 4.4572345;

		/* Returns the largest (closest to positive infinity) double value that is 
		less than or equal to the argument and is equal to a mathematical integer. */
		double floor = Math.floor(val);
		/* Returns the smallest (closest to negative infinity) double value that is 
		greater than or equal to the argument and is equal to a mathematical integer. */
		double ceil = Math.ceil(val);
		/* Returns the closest long to the argument, with ties rounding to positive infinity. */
		double round = Math.round(val);

		System.out.println(floor);
		System.out.println(ceil);
		System.out.println(round);
		System.out.println(roundDouble(val, 2));
		System.out.println(String.format("%1.2f", val));
	}
}

Output

4.0
5.0
4.0
4.46
4.46