Reason of this error ?

Question

I am trying to compile following code but compiler reporting a error .Plz someone explain me the reason of this error .
myvector.java:12: class MyNewVector is public, should be declared in a file named MyNewVector.java
Code is :
package foo;
import java.util.Vector;
private class myvector extends Vector {
int i = 1;
public myvector() {
i = 2;
public class MyNewVector extends myvector {
public MyNewVector() {
i = 4;
public static void main(String args[]) {
myvector v = new MyNewVector();
}

Answer 1

a .java file must contain one and only one class with the "public" attribute
it means that if you have "public class something" in a java file, this java file HAS TO BE named something.java
here, your .java must be called MyNewVector.java since your public class is MyNewVector