This change slims down the footprint of the deployed application in the event neither actuator nor web dependencies required. It also lets you switch between the reactive and conventional web paradigms by manually adding one of the following dependencies.

The following listing shows how to add the conventional web framework:

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
</dependency>

The following listing shows how to add the reactive web framework:

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>

The following list shows how to add the actuator dependency:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

One of the core themes for verion 2.0 is improvements (in both consistency and performance) around content-type negotiation and message conversion. The following summary outlines the notable changes and improvements in this area. See the “Chapter 9, Content Type Negotiation” section for more details. Also this blog post contains more detail.

JavaSerializationMessageConverter and KryoMessageConverter remain for now. However, we plan to move them out of the core packages and support in the future. The main reason for this deprecation is to flag the issue that type-based, language-specific serialization could cause in distributed environments, where Producers and Consumers may depend on different JVM versions or have different versions of supporting libraries (that is, Kryo). We also wanted to draw the attention to the fact that Consumers and Producers may not even be Java-based, so polyglot style serialization (i.e., JSON) is better suited.

The following is a quick summary of notable deprecations. See the corresponding {spring-cloud-stream-javadoc-current}[javadoc] for more details.

public interface Sample {
	String OUTPUT = "sampleOutput";

	@Output(Sample.OUTPUT)
	MessageChannel output();
}