Here you can find the source of isClassicAddress(InetAddress address)
public static boolean isClassicAddress(InetAddress address)
//package com.java2s; /*/*from w ww . ja v a 2 s.c o m*/ * Copyright 2010-2012 Roger Kapsi * * Licensed 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. */ import java.net.Inet4Address; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.SocketAddress; public class Main { /** * Returns true if the given {@link SocketAddress} is an IPv4 address */ public static boolean isClassicAddress(SocketAddress address) { return isClassicAddress(getAddress(address)); } /** * Returns true if the given {@link InetAddress} is an IPv4 address */ public static boolean isClassicAddress(InetAddress address) { return address instanceof Inet4Address; } /** * Returns true if the given address is an IPv4 address */ public static boolean isClassicAddress(byte[] address) { return address.length == 4; } /** * An utility method to get the {@link InetAddress} from the * {@link SocketAddress}. */ public static InetAddress getAddress(SocketAddress address) { return getResolved(address).getAddress(); } /** * Resolves (if necessary) the given {@link SocketAddress} and returns it. */ public static InetSocketAddress getResolved(SocketAddress address) { InetSocketAddress isa = (InetSocketAddress) address; if (isa.isUnresolved()) { return new InetSocketAddress(isa.getHostName(), isa.getPort()); } return isa; } /** * Returns {@code true} if the given {@link SocketAddress} is unresolved. */ public static boolean isUnresolved(SocketAddress address) { return ((InetSocketAddress) address).isUnresolved(); } /** * An utility method to get the {@link InetSocketAddress#getHostName()}. */ public static String getHostName(SocketAddress address) { return ((InetSocketAddress) address).getHostName(); } /** * Returns the port number. */ public static int getPort(SocketAddress address) { return ((InetSocketAddress) address).getPort(); } }