Spring Framework application high memory usage on start up - spring-boot

I have wrote REST APIs in java Spring Framework.
I have referred this github project and my project structure is very similar to this.
My application contains Spring Boot, Spring Security, Spring Security OAuth, Spring Data JPA and Spring mongodb.
I have observed that on start, the application consumes more than 100MB and increases 2MB on each URL request. Also mongodb connection is not closed automatically after some timeout.
I am not able to figure out this application start up memory usage. (is this because of spring boot or spring security or any other lib ?)
Is there any other best java framework for quick REST API development with Security, OAuth and MongoDB feature.
I want memory optimized REST APIs.

Related

is spring boot only for building rest api?

and if not what are more things that we can do with spring boot?
i know that we can build a whole web app(frontend and backend) in one spring boot application in the folder resource/template and resource/static but in the real world does somebody uses this method to create web application with the resource/template and resource/static?
and one more question what is used in the real world hibernate(with the SessionFactory or EntityManager) or JpaRepository in the spring data jpa?
No Spring Boot isn't just for REST APIs.
Spring Boot is "just" a mechanism for autoconfiguring a Spring Framework based application.
Therefore you can use and it does get used for all kinds of stuff.
REST APIs for webservices
Full web application using Spring MVC
SOAP services (or are they called SOAP dispensers?)
Reactive web applications
Command line tools
Batch jobs
Swing / JavaFX applications
...
Of course there are many more people writing web applications than Swing applications with or without Spring.
The kind of web application you describe and which I put under "Full web application using Spring MVC" is a very well established model and when done right way better aligned with the principles of REST than the average so called REST service. My very personal guess is: They will still be around when nobody remembers what Angular is.
For your additional question:
Your question sounds a little like the relation between JPA and Spring Data JPA might not be completely clear.
(see Spring Data JDBC / Spring Data JPA vs Hibernate)
Both are certainly used in real world projects. By definition more projects use JPA than Spring Data JPA since the first is a superset of the later.
This involves complete Spring history,
Actual motive of Spring was to enable loose coupling , so that unit tests can be easily performed . Spring MVC was for developing web applications with Model View Controller having their proper boundaries.
Then Spring Boot which enabled developer to focus on business logic then configurations. That's why spring boot is a good choice for microservices.
For JPA or hibernate query , many people prefer using JPARepositoy as again you just have to define entity for the repository and Spring boot automatically provides you queries like findById and so on.
In short Spring boot have made it really easy to run the applications with different configurations and environment smoothly.

Spring Boot - Reactive MongoDB: Random Access in GridFS?

How to random access chunks (start from any specific chunk, not necessarily from the first) in GridFS in Reactive MongoDB in the Spring Framework?
With the ReactiveGridFsTemplate available since Spring Boot 2.2 I cannot see any way.
Is there any low level method to do it?
NOTE: I opened a feature request in Spring Data Mongo Jira

Spring Cloud Data Flow - can it be used without spring boot?

Can Spring Cloud Data Flow be used in Spring5 applications - NOT Spring Boot - my current employer seems to view Spring Boot applications as insecure (I've no idea why) in anyway I'd like to try use this stack for an integration project, so is it possible to use it without Spring Boot?
With Spring Cloud Data Flow you can deploy streams, tasks and batches.
This is all based on Spring, Spring Cloud and Spring Boot. Spring Boot is nothing else as a preconfigured Spring stack.
Spring Data Flow is a runitme that usually needs a cloud infrastructure like Kubernets.
I'm not sure if you really are looking for that or more for something like https://spring.io/projects/spring-integration

Spring contract-first REST

I have a Spring web application - which doesn't use Spring-based GUI, but Wicket - and I would like to build contract-first REST services.
I already have a contract defined in Swagger and I generate model and API artifacts. Swagger codegen generates either Spring Boot artifacts, or Spring MVC ones.
My intention is to use ideally just a model, and maybe API (controllers) from this generated code. But up to my knowledge/research, there is no simple way to have just simple REST service without MVC/Boot boilerplate.
Therefore my questions are:
Is it possible to build lightweight Spring-based REST service, without having "heavy" dependency of full Spring MVC/Spring Boot?
If not, which approach is more lightweight? Spring Boot, or Spring MVC?
You are misinterpreting the Spring ecosystem.
Spring MVC is THE rest web and web service library within Spring portfolio.
The same way as Spring-WS is THE soap web service library.
They are very similar in architecture and style of use.
The fact that Spring MVC is bundled with Spring Framework does not change the situation.
Spring Boot does not bring any new REST offering. It is just a bootstrap mechanism to start Java web server with web app already deployed from a plain main() method. Therefore if you see "Building REST web services with Spring Boot", it just means that it is Spring MVC bootstrapped by Spring Boot.
Therefore, the question to what is more lightweight is straightforward: Spring MVC.
To answer the question #2:
The usage of Spring MVC is more lighweight, then usage of Spring Boot:
Size of the WAR archive:
6,1 MB for Spring MVC
9,2 MB for Spring Boot
Number of libraries in WAR archive:
12 for Spring MVC
28 for Spring Boot

Spring 3.2 web application and android client

I have a Web application with a db and it uses spring framework, hibernate etc. I need to send data from a mobile client (iphone,android) to web application like login, insert, update db etc. There are many ways to do that I think, however I am looking for a good solution. What would you prefer? Spring Security? REST?
Yes, spring-security to secure your service, and spring-web && spring-mvc with jackson dependencies to create an annotated rest service that you can host in something like tomcat.

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