Java two - Interface

Interface: a collection of constants and abstract methods set

Statement way:

public interface shape
{
    public static final PI=3.14;
    public abstract double area();
    public abstract double volume();
}

• Interface must use the interface keyword to declare
• Interface can be declared only constants and abstract methods
• Constant public static final statement [statement] is the default mode, can be omitted
• Method declaration] [public abstic same way as the default statement can be omitted

Interface Method:

• Interface methods are abstract method public authority, i.e., modified with abstract;
• The method gives only the method name, return values, the parameter table can not write the method body;

access permission:

• There are public access interface and default, but access to the interface only public

Interfaces and classes: