clarify azure main-class and boot plugin configuraitons

Author: tzolov

docs/src/main/asciidoc/adapters/azure-intro.adoc

@@ -98,6 +98,8 @@ TIP: Use the Java annotations included in the https://learn.microsoft.com/en-us/
 
 The implementation of the business logic used inside the Azure handlers looks like a common Spring application:
 
+[[HttpTriggerDemoApplication]]
+
 [source,java]
 ----
 @SpringBootApplication // <1>
@@ -130,7 +132,7 @@ For that purpose the `AzureFunctionUtil.enhanceInputIfNecessary` allow you to ad
 
 [source,java]
 ----
-@FunctionName("myazurefunction")
+@FunctionName("myfunction")
 public String execute(
 	@HttpTrigger(name = "req", authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
 	ExecutionContext context) {
@@ -163,7 +165,7 @@ public Function<Message<String>, String> uppercase(JsonMapper mapper) {
 
 In order to run Spring Cloud Function applications on Microsoft Azure, you have to use the Maven or Gradle plugins offered by Azure.
 Later imposes a specific https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-java?tabs=bash%2Cconsumption#folder-structure[package archive structure] that interferes with the `standard` Spring Boot package jars.
-The <<disable-spring-boot-layout,Disable Spring Boot Layout>> section below explains how to handle this.
+The <<disable-spring-boot-plugin,Disable Spring Boot Plugin>> section below explains how to handle this.
 You have to provide Azure specific configurations such as the `resourceGroup`, `appName` and other optional properties.
 More information about the runtime configurations: https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-java?tabs=bash%2Cconsumption#java-versions[Java Versions], https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-java?tabs=bash%2Cconsumption#specify-the-deployment-os[Deployment OS].
 
@@ -249,17 +251,33 @@ azurefunctions {
 The complete plugin documentation is available at the https://github.com/microsoft/azure-maven-plugins/tree/develop/azure-functions-maven-plugin[Azure Maven] and https://github.com/microsoft/azure-gradle-plugins/tree/master/azure-functions-gradle-plugin[Azure Gradle] repositories.
 
 
-==== Disable Spring Boot Layout
+==== Disable Spring Boot Plugin
 
-The Azure Functions come with their own (non-Boot) execution runtime that imposes its own packaging format generated by the Azure's maven/gradle plugins.
-Therefore we can't use the (standard) Spring Boot packaging.
-You have to either disable the Spring-Boot plugin all together or opt for the https://github.com/dsyer/spring-boot-thin-launcher[spring-boot-thin-launcher] instead.
-This https://github.com/spring-cloud/spring-cloud-function/blob/3bafcc59175fb61e323e393487d413441287a450/spring-cloud-function-samples/function-sample-azure-http-trigger/pom.xml#L97-L107[snipped] illustrates how to use the `spring-boot-thin-launcher` for Maven.
+Expectedly, the Azure Functions run inside the Azure execution runtime, not inside the SpringBoot runtime!
+Furthermore, Azure expects a specific packaging format, generated by the Azure Maven/Gradle plugins, that is not compatible with the default Spring Boot packaging.
 
-==== Provide Main-Class
+IMPORTANT: You have to either disable the SpringBoot Maven/Gradle plugin or use the https://github.com/dsyer/spring-boot-thin-launcher[Spring Boot Thin Launcher] as shown in this Maven snipped:
+
+[source,xml]
+----
+<plugin>
+	<groupId>org.springframework.boot</groupId>
+	<artifactId>spring-boot-maven-plugin</artifactId>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot.experimental</groupId>
+			<artifactId>spring-boot-thin-layout</artifactId>
+		</dependency>
+	</dependencies>
+</plugin>
+----
 
 [[star-class-configuration]]
-Next you must specify the `Start-Class` or `Main-Class` to point to your application main class.
+==== Main-Class Configuration
+
+Specify the `Main-Class`/`Start-Class` to point to your Spring application entry point, such as the <<HttpTriggerDemoApplication,HttpTriggerDemoApplication>> class in the example above.
+
+You can use the Maven `start-class` property or set the `Main-Class` attribute of your `MANIFEST/META-INFO`:
 
 ====
 [source,xml,indent=0,subs="verbatim,attributes",role="primary"]
@@ -284,23 +302,11 @@ jar {
 ----
 ====
 
-Alternatively you can explicitly set the main class using the `MAIN_CLASS` environment variable.
-
-For local runs, you can set the `MAIN_CLASS` in your the `local.settings.json`:
+TIP: Alternatively you can use the `MAIN_CLASS` environment variable to set the  class name explicitly.
+For local runs, add the `MAIN_CLASS` variable to your `local.settings.json` file and for Azure portal deployment set the variable in the https://learn.microsoft.com/en-us/azure/azure-functions/functions-how-to-use-azure-function-app-settings?tabs=portal#get-started-in-the-azure-portal[App Settings].
 
-[source,json]
-----
-{
-	"IsEncrypted": false,
-	"Values": {
-		... ,
-		"MAIN_CLASS": "YOUR-APP-MAIN-CLASS"
-	}
-}
-----
 
-IMPORTANT: When not set via the `MAIN_CLASS` variable, the Azure adapter will try to retrieve the main class from the `MANIFEST/META-INFO` sections of all dependencies.
-The first main class annotated with a `@SpringBootApplication` or `@SpringBootConfiguration` is selected.
+IMPORTANT: If the `MAIN_CLASS` variable is not set, the Azure adapter lookups the `MANIFEST/META-INFO` attributes from the jars found on the classpath and selects the first `Main-Class:` annotated with either a `@SpringBootApplication` or `@SpringBootConfiguration` annotation.
 
 ==== Configuration Metadata