Top Five Microframeworks along JVM

1) Micronaut:- Micronaut is JVM based Framework it has also support for UI it is completely full-stack framework however it is a microframework. You can either use JAVA, Groovy, Kotlin in order to create this particular Application.this is an example how you write code inside Micronauts.it exactly look like SpringBoot or in fact Spring MVC to be specific however you don't get heavyweight features like Spring does like this brings interceptor and stuff like that it is very basic and just gets up your server running as quickly as possible.you can write code in Java, Groovy and Kotlin.so you can familiar any one of these you can use it. 

It also provides native cloud support so if you are creating a Micronaut framework so you can easily integrate with that any of these cloud platforms. it also has seamless support to design patterns, for example, Eureka and Zipkin as well. if you need to connect any databases or any external source then you have to configure these and then you have to use toolkit and the libraries which are available you can integrate with it whenever you want. 

2) Spark:- Spark is another Microframework which is used to creating a web application using the Kotlin language and the Java 8 language as it says as minimal effort so you can write a web application with just minimum lines of code.if you want to create Microframework, Kotlin is your language Spark is your choice.  

3) Javalin:- The next framework which uses Kotin in conjugation with Java is the Javalin.this is another Microframework which is used for creating web Application it is exactly similar to Spark however it used its own way of creating web Application so see here

import io.javalin.Javalin;

public class HelloWorld {
    public static void main(String[] args) {
        Javalin app = Javalin.start(7000);
        app.get("/", ctx -> ctx.result("Hello World"));
    }
}

this framework is lightweight framework the only difference between them is the way are they implemented.this uses a declarative style for creating your Application.

4) Ktor:- This is again a merger of Kotlin and Java however you will be writing in Kotlin Specifically so it will be running on the JVM but you will be writing completely in Kotlin 

It is also declarative you can write something like embedded server routing. these frameworks are very simplistic and you will write code in a simpler way the idea of this framework to make your application flexible and simple & fast enough to boot within seconds. Ktor is Kotin Specific framework.

5) Dropwizard:- Dropwizard is another framework which people are using mostly it is very lightweight as well compared to the SpringBoot and other frameworks for microservices it has lots of support toward Configuration, Application Monitoring, logging etc.

So these are the some of the microframeworks which work along with JVM .these are evolving people are trying out and since serverless frameworks and the container based frameworks are in the evaluation these frameworks adopted very slowly once we get serverless architecture and container-based architecture are more popular we will be able to see frameworks evolving in due course of time.