Please, help

I want to create just a simple Node so i write the program shown below :

import ants.core.Node;
import ants.core.UnknownMidPackets;
import ants.core.security.Principal;
import ants.core.security.SecurityDefaults;

import edu.utah.janos.nodeos.Flow;

public class NoeudANTS extends Node
{
NoeudANTS(Flow flow,UnknownMidPackets unknownMidPacket,Principal principal)
{
super(flow,unknownMidPacket,principal);
}

static public void main(String[] args)
{
    UnknownMidPackets unknownMidPacket=new UnknownMidPackets();
    Principal principal=SecurityDefaults.BOOTSTRAP_USER;
    Flow flow=Flow.currentFlow();

NoeudANTS noeudANTS=new NoeudANTS(flow,unknownMidPacket,principal);

System.out.println("Le noeud est cree");
}
}

There no errors in compilation but when i try to execute it, he show me the next error's message:

Exception in thread "main" java.lang.NoClassDefFoundError: NoeudANTS (wrong name: ants/core/NoeudANTS)
        at java.lang.ClassLoader.defineClass0(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:486)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:111)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:248)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:297)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:286)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:253)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:313)

So please, can someone tell me where is the problem and quickly please.