The first interface interface

. 1  Package Interface;
 2  
. 3  / * 
. 4      how to define an interface:
 . 5      public interface Interface Name {
 6          // interface content
 7      }
 8   * / 
. 9  
10  / * 
11     using the interface step:
 12     1 interface can not be used directly, there must be a "implementation class" to "realize" the interface
 13     format:
 14     public class implements the interface implementation class name {name
 15          // ....
 16     }
 17     class that implements the interface must overwrite 2 (implement) the interface All the abstract methods,
 18     to achieve: to remove the abstract keyword, plus the method body braces.
19     3. Create an object implementation class, use.
20  
21     Note:
22     If the class does not implement all of the abstract methods interface overwritten, then the implementation class and that it must be abstract class.
23 is  * / 
24  public  class Demointerstate {
 25      public  static  void main (String [] args) {
 26 is          // Error writing can not directly use the new interface object
 27  
28          // create objects using implementation class 
29          MyinterfaceAbstrctImpl impl = new MyinterfaceAbstrctImpl ();
 30          impl.methodAbs ();
 31 is      }
 32 }

. 1  Package Interface;
 2  
. 3  public  class MyinterfaceAbstrctImpl the implements MyinterfaceAbstract {
 . 4      @Override
 . 5      public  void   methodAbs () {
 . 6          System.out.println ( "This is the first method!" );
 7      }
 8 }

. 1  Package Interface;
 2  / * 
. 3  * in any version of Java, the interface can define the abstract methods.
4  * format:
 . 5  * public abstract method return value name (parameter list);
 6  * Note:
 7  * abstract method 1. Among the interfaces, the modifier must be fixed two keywords: public abstract
 . 8  * 2. both keywords modifiers, may optionally be omitted (not recommended)
 . 9  * / 
10  public  interface MyinterfaceAbstract {
 . 11      // this is an abstract method 
12 is      public  abstract  void methodAbs ();
 13 is }