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Kotlin program to find IP address of Windows/Linux System

Kotlin | Find IP Address: Here, we are going to learn how to find IP address of a Windows or Linux System in Kotlin programming language?
Submitted by IncludeHelp, on May 05, 2020

The task is to find IP address of the system.

package com.includehelp

import java.net.Inet4Address
import java.net.InetAddress
import java.net.NetworkInterface

//Function to Find out IP Address
fun getSystemIP(): String? {
    return try {
        var sysIP: String?
        val osName = System.getProperty("os.name")
        if (osName.contains("Windows")) {
            sysIP = InetAddress.getLocalHost().hostAddress
        } else {
            sysIP = getSystemIP4Linux("eth0")
            if (sysIP == null) {
                sysIP = getSystemIP4Linux("eth1")
                if (sysIP == null) {
                    sysIP = getSystemIP4Linux("eth2")
                    if (sysIP == null) {
                        sysIP = getSystemIP4Linux("usb0")
                    }
                }
            }
        }
        sysIP
    } catch (E: Exception) {
        System.err.println("System IP Exp : " + E.message)
        null
    }
}

//For Linux OS
fun getSystemIP4Linux(name: String): String? {
    return try {
        var ip : String?=null
        val networkInterface = NetworkInterface.getByName(name)
        val inetAddress = networkInterface.inetAddresses
        var currentAddress = inetAddress.nextElement()
        while (inetAddress.hasMoreElements()) {
            currentAddress = inetAddress.nextElement()
            if (currentAddress is Inet4Address && !currentAddress.isLoopbackAddress()) {
                ip = currentAddress.toString()
                break
            }
        }
        if (ip != null) {
            if (ip.startsWith("/")) {
                ip = ip.substring(1)
            }
        }
        ip
    } catch (E: Exception) {
        System.err.println("System Linux IP Exp : " + E.message)
        null
    }
}

//Main Function, Entry Point of Program
fun main(args: Array<String>) {

    //Call Function to get IP Address
    val ipAddress = getSystemIP()

    //Print IP Address
    println("System IP : $ipAddress")
}

Output

System IP : 192.168.43.41