More puzzling behaviour

Still in the spirit of Java Puzzlers; can you provide declarations for i and j to make this statement fail at runtime?

i = j;

I spent quite some time debugging this, once...

Puzzling behaviour

In the spirit of Java Puzzlers, what does this program print (if anything)?

public class java
{
    static lang lang = new lang();
    
    static class lang
    {
        static Long Short = new Long();
        
        static class Short
        {
        }

        static class Long
            extends Short
        {
        }
    }
    
    public static void main(String[] args) {
        System.out.println(java.lang.Short.class.getSimpleName());
    }
}