main class could not be found or loaded even tough there is a main method

Question

I have two classes ChatClient and Listener and want to comile and run them. In eclipse it works fine, but on terminal I can't get it run. Both classes are on the path: /Desktop/java/task4 . Maybe I should mention that inside the ChatClient class a Listener Object gets created.

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I compile the two classes with the command: javac *.java and get 2 classes created. But if I type java ChatClient I get the error main class could not be found or loaded . What am I doing wrong? I'm using Ubuntu. And yes there is a main method inside ChatClient

public class Listen extends Thread {
Socket s;
Scanner msg;

public Listen(Socket s) {
    ....

}

---

public class Chatter {


public static void main(String[] args) {
    try {
        ...
        Listener lt = new Listener(s);
        ...
}

Answer 1

There are many possibilities are there to get this error, while running from cmd. Because IDE will do many things related to class path in back ground.

Highest possibility of getting this error is, beginners will not aware of giving the full package structure while running using `java cmd` from correct classpath directory. Please go to this link for more information.

Answer 2

The obvious problem is that you class is in a package ( UE3 ) but you have not used the full qualified class name. Try:

java UE3.ChatClient

There are many other possible problems, such as the classpath not being setup correctly.

(Note the convention for package names is all lowercase. Also rather than extending Thread you should typically pass in a Runnable as a lambda or method reference.)