Error running this example

Question

On my computer, I get the following msg while i try to do the exercise here,

interface Animal {
public void eat();
public void makeSound();
}
class Cat implements Animal {
public void makeSound() {
System.out.println("Meow");
}
public void eat() {
System.out.println("omnomnom");
}
}
public class Program {
public static void main(String[] args) {
Cat c = new Cat();
c.eat();}}

Error: Could not find or load main class undefined
what did I do wrong?

Answer 1

Post the code so that we can try to help.

Answer 2

Yes but you need to put them into same package so that your Program class can load classes from others.

Answer 3

It means you didn't save your Java file same name as your class. Do you have Program.java Cat.java, 2 files? Are they using same package? I think you didn't name your main method class file, Program.java that is why JVM cannot detect your main method from Program.java

Answer 4

does that mean that i can keep multiple classes in one file as long as it's named after the one that has the main?