Can we use private or protected member variables in an interface?

Question

Is it possible to define an interface like this:

public interface Test{
   public string name1;
   private String email;
   protected pass;
}

Answer 1

When you Declare interface The java compiler adds public and abstract keywords before the interface methods and public, static and final keywords before data members automatically

public interface Test{
   public string name1;
   private String email;
   protected pass;
}

as you have declare variable in test interface with private and protected it will give error. if you do not specify the modifier the compiler will add public static final automatically.

public interface Test{
   public static final string name1;
   public static final  String email;
   public static final pass;
}

The most important thing is that

1. Interfaces cannot be instantiated that is why the variable are static

2. Interface are used to achieve the 100% abstraction there for the variable are final

3. An interface provide a way for the client to interact with the object. If variables were not public, the clients would not have access to them. that is why variable are public