Module 3- Example 16,17

In Ex16 we are not able to declare class JavaClass variable as static JavaClass obj(getting error msg - JavaClass cannot resolve to a type)however its working fine for Ex17 where the Class name is Ex17. Please explain the reason behind that.

Ex16---
public class Javaclass {
static int i;
static JavaClass obj;
public static void main (String[] args) {

System.out.println(++i); //obj + "" +i);


}
}
Ex17---
public class Ex17 {
static int i;
static Ex17 obj;
public static void main (String[] args) {

// Ex17 obj;
int i=1;
System.out.println(i);// obj + "" +i);



}
}