SpringBoot 3.0 features

1. Java 17 as baseline for long term support

2. Jakarta EE support with servlet 5.0 and JPA 3.0 specification. Javax package is now migrated to Jakarta EE, so we need to import those packages accordingly

3. SpringNative support with Gral VM to compile spring application into local executable image file, reduces memory footprint ,improve the start up time to boot

4. Observability support- can publish metrices to grafna or any other platform

5. ProblemDetail-With ProblemDetails we can map http specific error in application

6. dependcny upgrade - Java 17 support minimum, lombok 1.18 onward,gradle 7.3 onward

7. HttpExchange --declarative way of defining rest client, need spring reactive web in pom.xml

8. Spring Framework 6.0 support

AsJava 17 feature, we can make use of record classes instead of DTO classes as below

record is by default final,all varibale are private ,final. it is immutable and provide thread safty. it does not have setter and getter and can not define it also. with filed name only we get method to access that field. It simply servee the purpose of data carrier as DTO.

ProblemDetail--

Noramlly we create Error class with various attribute like error code,status code,message and then make use of this class as part of exception handling. From Java17 onward, this funcationality is now supported by ProbelmDetail.

Please see code snippet for reference.

problemdetail have below api.

Observability

With observability , we can publish metrcies for application in spring cloud infrastructure with zipkin and sleuth. It can also be published and visualized with grafana.

Below package we need to use for the observability support

code snipet

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Here we are monitoring all api operation of rest endpoint

metrcis name - addCustomer ---for addcustomer endpoint

getCustomer-----for getCustomer endpoint

we are making use of observation registry to monitor metrcies and publish it to macrometer so that it can be used by 3rd party tool like promotheus,grafana

once we successfully test our endpoint , we can track our metrcies on actuator/metrcies as below and can see our metrices

@HttpExchange

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Declarative way of defining rest client for consuming rest api endpoint

we need to consume below api endpoint

endpoint - /customerinfo

method-- GET

return type -- list of customer

will define client package and in that we will define interface to comsume api asbelow

depending on type of methos , we can have below HttpExchange

to consume api endpoint, we will make use of below

now we can not create instance of interface, we need to have bean of webclient and register this interface with it so that spi can be consumed

register cusotmerclientservice with httpserviceproxyfactory as below

Springboot 3.1.1 migration

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update springboot version from 2.7.3 to 3.1.1

update java version to 17

update cloud version

please note that for every project, just create same project in spring initializer with same dependency as we have for our existing project, this will give any

dependency need to be updated or any version or name for the dependency to be updated

for example:

zipkin , sleuth is now replaced by micrometer brave and zipkin reporter, okta is now being revised to new version

so those above changes we need to make for our migration, elaode maven project, all latest jar will be downloaded, start project

we may find compile time error for javax package as it is moved to Jakarta, so change import for Jakarta

sping6 has deprecated antMatvher , it is now requestMatcher, just use this.

replace @EnableEurekaClient with EurekaDiscoveryClient