I have developed my first Spring Boot application and packaged a JAR using Maven.
When I launch it on my machine, no issues.
When a different client launches it they will get an error if they don't have the same version of Java as I developed it in (Java 8).
I had made the assumption that everything would be packaged into a self contained JAR with everything it needs to run (like when I create native packaging with JavaFX).
Am I missing something? What are the best practices for distribution a Spring Boot JAR? Thanks in advance.
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I have a spring-boot application in which I loaded all the necessary (or so I believe) dependencies to run without using spring-boot initializer or the spring-boot gradle plug-in. These tools are not available for me at my work. I can run the application through intellij without issues, but when attempting to run a fat jar, I am met with
No auto configuration classes found in META-INF/spring.factories.
Now the spring.factory files ARE located inside the fat jar (there are multiples of them) and they are inside the meta-inf directory.
Spring boot has so much automated functionality, I am not sure where to begin. There are a lot of similar posts and everyone just tells people to use the spring-boot gradle plugin bootJar task but as I said these are not available to me. I need to get it running without those tools,
if anyone has insight into what the issue may be or how to resolve it, any help is appreciated. I will try to add more details later.
I am using spring-boot v. 2.1.1 and spring 5.1.4
I know spring boot applications can be deployed to production environments as war files. But what is the typical way of deploying spring boot applications? Does it only require a jvm, not a container?
The Spring Boot Project Page states that Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can "just run".
Means by default, the Spring Boot maven or gradle plugin builds self-contained executable jars, that contain all dependencies and an embedded webserver, e.g. tomcat or jetty. The Spring Boot Getting Started doc gives you an introduction to that. Using this approach you just need a JVM to run your application. But you can also configure it to create war files if this is a better fit to your production environment.
Does it only require a jvm, not a container?
It can run anywhere Java is setup.
Spring Boot's use of embedded containers and why Spring chose to go the container-less route. Many of their main driving forces were ease of use while testing and debugging, and being able to deploy Spring-based Java applications to the cloud, or any other environment.
Rest can be found out in attached image.
Spring boot applications if they are serving web requests do require a container. You can either deploy them as a war inside a container such as tomcat/jetty. Or you can deploy them with embedded container, tomcat.
I currently have a project running on JRuby which is packaged in a WAR and deployed on TC Server / tomcat.
I was looking into spring boot and I am wondering if someone can explain how easy / hard it would be to convert that application to run on Spring Boot on JRuby.
.war is packed up as "standard" JavaEE project (see the generated web.xml) - nothing fancy really.
that means that you could add whatever libraries and additional files as you want as long as you understand the JRuby-Rack bootup process. your question is kind of vague as of how Spring should interact with JRuby or if it won't need to interact at all. if not simply add another context listener to boot spring, include the spring .jar files and map the URL handling accordingly.
I am new to Spring MVC and I have now come accross tutorials that explain how to deploy your web project as a .jar. My IDE is the Spring Tool Suite. I have always used .war + Apache Tomcat.
Can someone elaborate a bit from the practical point of view why to use .jar instead of .war? Any problems to be aware of?
edit: other answers are welcome too
Spring Boot uses fat JAR packaging where is embeds Servlet container with all dependencies into this single JAR.
If you are using Maven, it uses spring-boot-maven-plugin to package the project.
Practical usage of this approach is simple. Ability to easily run Srvlet based Spring application from command line with externalized properties. Such configuration enables powerfully orchestration possibilities which are often used in modern enterprises in so called Microservices or SOA architecture.
There is group of people out there (including myself) which believe that deploying various WAR files of unrelated applications into single Servlet runtime is not very good idea.
So fat JARs are handy for separate Servlet runtime per application deployment.
About having .jar and Tomcat + .war on the same machine, it is possible and I use this. This may be not cool but I had a .war application running in a tomcat server before the rise up of spring boot. Now my new apps are spring boot apps, and we are migrating our architecture to SOA concept, but we can't change the tire with the moving car. The main application, the WAR is running in a tomcat server and the others (.jar) are self contained ( embedded tomcat ), each one running in a different port. It was the most viable solution available for us by the moment.
I've been reading about using Spring Boot and Gradle to quickly build RESTful services: https://spring.io/guides/gs/rest-service/. I'd like to give it a try but I need to build a war that's compatible with servlet 2.4 (I know.. life in the 1970's).
The error I get when attempting to deploy the war generated by following the guide above to Sun App Server 8.1 is:
Unknown deployable object type specified: "Cannot determine the J2EE
component type"
The generated war has no web.xml and there may be other expected artifacts.
Configuring a spring-boot application using web.xml seems to suggest that a web.xml can be packaged with a Spring Boot application but doesn't explain how.
Is Spring Boot compatible with older servlet specs? How can Spring Boot and Gradle be used to generate a war that works on older web containers?
Thanks.
The answer to the question you linked to didn't actually go as far as saying that you could easily create a fully-leaded Boot application with Servlet 2.4. I consider that quite a hard, but probably achievable, target if you are prepared to do some legwork, and accept some compromises. You might find this stuff useful: https://github.com/scratches/spring-boot-legacy (I managed to use it to push an app to GAE). But there are some limits to what can be supported for such old technology, and we aren't officially supporting anything other than Servlet 3.0.1 right now.