Class inside Interface, Class inside Class , Interface inside Class , Interface inside Interface,

Class inside Interface
 example:
 public interface InterfaceA {
    class ClassA{
      
    }
}

Class inside Class 
 example:
 public class ClassA {
  
    class ClassB{
      
    }
}

Interface inside Class
 example:
public class ClassA {
   
    interface InterfaceA{
       
    }
}

Interface inside Interface
example:
public interface InterfaceA {
    interface InterfaceB{
       
    }
}