Here you can find the source of toSortedIntArray(Collection
public static int[] toSortedIntArray(Collection<Integer> ints)
//package com.java2s; /******************************************************************************* * Breakout Cave Survey Visualizer//from w w w . j ava2 s .c o m * * Copyright (C) 2014 James Edwards * * jedwards8 at fastmail dot fm * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *******************************************************************************/ import java.util.Arrays; import java.util.Collection; public class Main { public static int[] toSortedIntArray(Collection<Integer> ints) { int[] result = toIntArray(ints); Arrays.sort(result); return result; } public static int[] toIntArray(Collection<Integer> ints) { int[] result = new int[ints.size()]; int k = 0; for (int d : ints) { result[k++] = d; } return result; } }