在Java中獲取Linux系統的IP地址可以通過以下幾種方法：

1. 使用InetAddress類：

import java.net.InetAddress;
import java.net.UnknownHostException;

public class GetIPAddress {
    public static void main(String[] args) {
        try {
            InetAddress address = InetAddress.getLocalHost();
            System.out.println("IP Address: " + address.getHostAddress());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

2. 使用NetworkInterface類：

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;

public class GetIPAddress {
    public static void main(String[] args) {
        try {
            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
            while (interfaces.hasMoreElements()) {
                NetworkInterface networkInterface = interfaces.nextElement();
                Enumeration<InetAddress> addresses = networkInterface.getInetAddresses();
                while (addresses.hasMoreElements()) {
                    InetAddress address = addresses.nextElement();
                    if (!address.isLoopbackAddress() && address.getHostAddress().indexOf(":") == -1) {
                        System.out.println("IP Address: " + address.getHostAddress());
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

這兩種方法都可以獲取Linux系統的IP地址，其中第一種方法是獲取本地主機的IP地址，而第二種方法則是獲取所有網絡接口的IP地址。根據你的需求選擇合適的方法獲取IP地址即可。