Cannot run on server

[Eleeist]

Hi,

I am trying to do a basic networking. Both client and server programs work when I run them in IDE on my local machine. However, when I upload my server code (NetworkingServer.class) to the server (Debian with openjdk) and try to run it with "java NetworkingServer" I get these errors:

Exception in thread "main" java.lang.NoClassDefFoundError: NetworkingServer (wrong name: networkingserver/NetworkingServer)
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
	at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
	at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:334)
Could not find the main class: NetworkingServer. Program will exit.

The code:

package networkingserver;

import java.net.*;
import java.io.*;

public class NetworkingServer {
    
    public static void main(String[] args) throws IOException {

        ServerSocket serverSocket = null;
        Socket clientSocket = null;
        
        try {
            serverSocket = new ServerSocket(4444);
        } catch (IOException e) {
            System.err.println("Could not listen on port: 4444");
            System.exit(1);
        }
        
        try {
            clientSocket = serverSocket.accept();
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        clientSocket.close();
        serverSocket.close();
        
    }
    
}

[Norm]

java.lang.NoClassDefFoundError: NetworkingServer (wrong name: networkingserver/NetworkingServer)

The class is in a package: networkingserver. Wherever you specify the class name you need to include the package in the name.
Or remove the class from the package.

[Eleeist]

Wherever you specify the class name you need to include the package in the name.

What do you mean, exactly?

[Norm]

I don't know how you configure the server. If there is a place for you to enter a class name, use the full class name that includes the package:
For example: classname=thepackage.TheClass

There is some code trying to load your class that only uses: TheClass, it should use thepackage.TheClass
That is what the error message is saying. It read the class file and found the classname included a packagename but that packagename was not included.

Sometimes it is simpler to remove the package statement from your source.

[Eleeist]

Ok, I think I get it know. I just remove the package name and have been able to run it without any problems. Thank you for you help :).