Here you can find the source of copyOf(Integer[] original)
public static Integer[] copyOf(Integer[] original)
//package com.java2s; /**//from ww w. ja v a 2 s . c om * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ public class Main { public static Integer[] copyOf(Integer[] original) { int len = original.length; Integer[] copy = new Integer[len]; System.arraycopy(original, 0, copy, 0, len); return copy; } }