Intro

https://microservices.io/
https://javabrains.io/topics/
https://www.youtube.com/channel/UCYt1sfh5464XaDBH0oH_o7Q

Microservices is mainly for Continous Delivery

annotation is part of a compilation.



Sprint boot is a wrapper on Spring

Spring is a framework EJB is a specification
hibernate(RedHat) is not std so jpa came(specification)

the container is a pre-written program provides below feature
1.life cycle management
2.declarative services(txn,security,cache ,logging,exception handling etc) pattern used proxy
3.Distribute env or remoting  (Protocols)

Lightweight means small life cycle

IOC,DI(Dependency Injection) & AOP(pointcut)

Spring Life cycle comes with 8 steps

1. Instantiate
2. populate propertie
3. beanname awares setbeanName()
4. Bean FactoryAwares's setBeanFactory()
5. Pre-initialization Bean Post processors
6. InitializingBeans afterPropertiesSet()
7. Call custom init-methos
8. post initialization beanpostprocessors

1,2,3,5,6,7  are bean specific 6 and 7 we can ignore
4,8 post processor are not optional .power of spring relies on this steps

there are inbuild and custome post processors
jsr 250 class common annotationbeanpostprocessor
class autowiredannotaionbeanpostprocessor


Bean Post Processors:
this are special beans registered to the factory as part of life cycle all the bans must go through the post processors


spring life cycle uses builder pattern t construct bean

builder ->is object scope (composition), creational, bean construction, some of the steps are optional

teamplete-> class inheritance(behavioral pattern), bean execution, all the steps are mandate

So spring boot came to remove this MVC(Above one)

Setting java path and variable

To start spring-boot

https://start.spring.io/


any changes will reboot the application

spring boot is mainly rest


@Configuration->@bean (Pojo)
@componentscan-> @component(AOP)
                                 @controller(PT)
                                 @service(BT)
                                 @repository(DT)
@EnableAutoConfiguration(EnableJms,EnableTransactionManagement,EnableWebMVC)


OOAD---->OCP(Open CLose Programme)


Any application  closed for modification open for extension

@Decorateor

---------------------------
yml

follows hierarchy json. PERFORMANCE ALSO SUPER

server
  port
     http   . its like server.port.http


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use rest template to use one service in one server to another service is a different server

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spring is mainly of setter and constructor injection

@autowired is similar to interface injection

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Service Registry

Tools:  Apache zookeeper, Netflix, Consul
MOcroservceis->Spring, Spring Boot, Spring cloud Netflix components




cloud-native application or platform

to get the advantage of cloud computing model the application must have 4 characteristics

1.devops.
2.continous delivery
3.micro services
4.contaionarization(locker,gorden)



maven package: wi;; create a jar of the project in the workspace
maven install: generate files in maven repository




to enable actuator we need the below dependencies
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

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management:
  endpoints:
    web:
      exposure:
        include:
          heapdump,metrics,info,health,shutdown,threaddump,env
 
  endpoint:
    shutdown:
      enabled: true
      --------------------------------------------------------------
Hateoas(hypermedia as the engine of application sate) is a constraint of the rest application architecture

a hypermedia driven site provides information to navigate the sites rest interace
dynamically by including hypermedia links with the responses

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rest  documentation

swagger ---mainly used
post man---mainly used
hateoas---for spring boot, makes navigation easy in spring boot
wadl
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jms-> java messaging system
JMX->java management extension
   -> mainly for runtime managment

jconsole is the management client application
mbean can be managed at run time
---------------------------------
garbage collector-> identifies live/reference  objects and rest it will sweep.

rot johnson created spring 

java persistance(JPA) with hibernet gavin kin

micro services by martin fowler

micro services by richerson

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