A single pattern is divided into two cases:
(1) Single starving Example: class loading stage creates an object.
(2) lazy single example: the object will use the time to create the object. (Examples 53 is serialized in the lazy formula)
Example starving the formula:
package com.bjpowernode.java_learning; public class D54_1_HungtySingtonMode { public static void main(String[] args) { Customer54 c1 = Customer54.getCustomer54(); Customer54 c2 = Customer54.getCustomer54(); System.out.println(c1==c2); } } //饿汉式单例模式 class Customer54{ private static Customer54 c = new Customer54(); private Customer54() {} public static Customer54 getCustomer54(){ return c; } }
Second, the interface is also a reference type, the class can be seen as equivalent
1. How to define the interface, syntax:
[Modifier] interface interface name ()
Constant, abstract methods: 2. The interface can only appear
3. In fact, the interface is a special abstract class, a special interface is completely abstract
4. The method of the interface is not configured, it can not be instantiated
Inheritance can be more and the interface between the interface 5
6. A class can implement multiple interfaces. (Here the "realization" can be seen as equivalent to "inherit")
7. A non-abstract class implements an interface, the interface will need all methods "implemented / rewrite / coverage"
Package com.bjpowernode.java_learning; public interface D54_2_InterfaceExercise { public static Final String = SUCCESS "Sucess" ; public static Final Double the PI = 3.1415926 ; // public static Final may be omitted in the interface, since the syntax rules as known, only It can be a constant byte MAX_VALUE = 127 ; public abstract void M54 (); // abstract method void test54 (); // this is the abstract methods public abstract are herein may be omitted. Same reason } interface B54 { void M2 (); } interface the C54 { void M3 (); } interface D54 { void M4 (); } interface E53 the extends B54, the C54, D54 { void M5 (); } // the implements are achieved mean // Since a single inheritance class, so here the new keyword implements to achieve class MyClass implements B54, C54 { public void m2 () {} // Because m2 is the original abstract methods, here we have a new class overwrites the m2 method public void M3 () {} } class F54 the implements the E54 { public void M2 () {} public void m3 () {} public void m4 () {} public void m5 () {} }
We had an example in accordance with the above seven syntax.
Third, the role of the interface (look at an example, say the next summary)
package com.bjpowernode.java_learning; public interface D54_3_CustomerService { void logout(); }
Package com.bjpowernode.java_learning; public class D54_4_ImplementCustomer { public static void main (String [] args) { // The following program interface to call for D54_3_CustomerService D1 = new new D54_4_ImplementCustomerService (); // polymorphism d1.logout (); / / underlying classes, the interface type, the method can be used in the interface, since the bottom is the actual call type, the methods used in the actual class } } class D54_4_ImplementCustomerService the implements D54_3_CustomerService { // abstract interface methods will be implemented public void Zimbabwe Logout () { System.out.println ( "successfully exit the system!"); } }
Fourth, the source code:
D54_1_HungtySingtonMode.java
D54_2_InterfaceExercise.java
D54_3_CustomerService.java
D54_4_ImplementCustomer.java
address:
https://github.com/ruigege66/Java/blob/master/D54_1_HungtySingtonMode.java
https://github.com/ruigege66/Java/blob/master/D54_2_InterfaceExercise.java
https://github.com/ruigege66/Java/blob/master/D54_3_CustomerService.java
https://github.com/ruigege66/Java/blob/master/D54_4_ImplementCustomer.java
2.CSDN: https: //blog.csdn.net/weixin_44630050 (Xi Jun Jun Moods do not know - Rui)
3. Park blog: https: //www.cnblogs.com/ruigege0000/
4. Welcomes the focus on micro-channel public number: Fourier transform public personal number, only for learning exchanges, backstage reply "gifts" to get big data learning materials
