Here you can find the source of format(double d, int decimals)
public static String format(double d, int decimals)
//package com.java2s; /*/* ww w . ja va 2s. c o m*/ * Copyright (c) 2016 Vivid Solutions. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * and Eclipse Distribution License v. 1.0 which accompanies this distribution. * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html * and the Eclipse Distribution License is available at * * http://www.eclipse.org/org/documents/edl-v10.php. */ public class Main { /** * Returns d as a string truncated to the specified number of decimal places */ public static String format(double d, int decimals) { double factor = Math.pow(10, decimals); double digits = Math.round(factor * d); return ((int) Math.floor(digits / factor)) + "." + ((int) (digits % factor)); } }