noclassdeffounderror在一个简单的网络程序中。我正在使用EclipseIDE运行java程序

Question

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

class IpAddr {
    public static void main(String arg[]) {
        System.out.println("Hello Jagadeesh...>!!");
        try {
            InetAddress ia=InetAddress.getByName("www.facebook.com");
            System.out.println(ia);
        }
        catch(UnknownHostException uhe) {
            System.out.println("ip address of facebook is not found. :(");
        }
    }
}

在控制台中：运行时 E:\myworkspace\network\u practice\src\stage1>；javac-IpAddr。JAVA E:\myworkspace\network\u practice\src\stage1>；java IP地址

Exception in thread "main" java.lang.NoClassDefFoundError: IpAddr（错误名称：s） tage1/IpAddr）

at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

E:\myworkspace\network_practice\src\stage1>cd..

Answer 1

你没有在你的类中声明一个包，所以它进入默认包。但你有stage1文件夹

Answer 2

贾加迪什， 在这种情况下，您的InetAddress jar版本可能不受支持

Answer 3

NoClassDefFoundError in Java comes when Java Virtual Machine is not able to find a particular class at runtime which was available during compile time.

资料来源：http://javarevisited.blogspot.de/2011/06/noclassdeffounderror-exception-in.html

因此，我会检查您是否已将所有必需的内容添加到类路径中