I have the following code that makes an abstract class, concrete class that extends abstract class and a main method. There are no errors as it compiles and run fine in JGRASP. when I run in eclipse, it is just not running, but no errors produced. I named the file Product.java.

Here is the code:

```
abstract class Product {
    int value;

    public Product(int val) {
        value = val;
    }

    abstract public int multiply(int n);
}

class TimesTwo extends Product {
    public TimesTwo(int val) {
        super(val);
    }

    @Override
    public int multiply(int n) {
        return value * n;
    }

    public static void main(String[] args) {
        TimesTwo two = new TimesTwo(5);
        System.out.println(two.multiply(5));
    }

}

```

I also try to run on commandline:

```
javac Product.java

```

I get `Product.class` and `TimesTwo.class`

and when I run 
`Java TimesTwo.class` or `Java Product.class`

I get `Exception in thread "main" java.lang.NoClassDefFoundError:`