Switch Java versions used in documentation

See gh-32746

spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/using-the-cli.adoc

@@ -136,11 +136,11 @@ You can list the capabilities of the service by using the `--list` flag, as show
 
 The `init` command supports many options.
 See the `help` output for more details.
-For instance, the following command creates a Gradle project that uses Java 8 and `war` packaging:
+For instance, the following command creates a Gradle project that uses Java 17 and `war` packaging:
 
 [source,shell,indent=0,subs="verbatim"]
 ----
-	$ spring init --build=gradle --java-version=1.8 --dependencies=websocket --packaging=war sample-app.zip
+	$ spring init --build=gradle --java-version=17 --dependencies=websocket --packaging=war sample-app.zip
 	Using service at https://start.spring.io
 	Content saved to 'sample-app.zip'
 ----

spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/cloud.adoc

@@ -45,7 +45,7 @@ At this point, `cf` starts uploading your application, producing output similar
 	Preparing to start acloudyspringtime... *OK*
 	-----> Downloaded app package (*8.9M*)
 	-----> Java Buildpack Version: v3.12 (offline) | https://github.com/cloudfoundry/java-buildpack.git#6f25b7e
-	-----> Downloading Open Jdk JRE 1.8.0_121 from https://java-buildpack.cloudfoundry.org/openjdk/trusty/x86_64/openjdk-1.8.0_121.tar.gz (found in cache)
+	-----> Downloading Open Jdk JRE
 	       Expanding Open Jdk JRE to .java-buildpack/open_jdk_jre (1.6s)
 	-----> Downloading Open JDK Like Memory Calculator 2.0.2_RELEASE from https://java-buildpack.cloudfoundry.org/memory-calculator/trusty/x86_64/memory-calculator-2.0.2_RELEASE.tar.gz (found in cache)
 	       Memory Settings: -Xss349K -Xmx681574K -XX:MaxMetaspaceSize=104857K -Xms681574K -XX:MetaspaceSize=104857K
@@ -179,8 +179,8 @@ Which will result in the following:
 	Total 95 (delta 31), reused 0 (delta 0)
 
 	-----> Java app detected
-	-----> Installing OpenJDK 1.8... *done*
-	-----> Installing Maven 3.3.1... *done*
+	-----> Installing OpenJDK... *done*
+	-----> Installing Maven... *done*
 	-----> Installing settings.xml... *done*
 	-----> Executing: mvn -B -DskipTests=true clean install
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/installing.adoc

@@ -1,7 +1,7 @@
 [[getting-started.installing]]
 == Installing Spring Boot
 Spring Boot can be used with "`classic`" Java development tools or installed as a command line tool.
-Either way, you need https://www.java.com[Java SDK v1.8] or higher.
+Either way, you need https://www.java.com[Java SDK v17] or higher.
 Before you begin, you should check your current Java installation by using the following command:
 
 [source,shell,indent=0,subs="verbatim"]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/spring-mvc.adoc

@@ -35,8 +35,7 @@ If Jackson's XML extension is not available and JAXB is available, XML can be re
 
 include::code:MyThing[]
 
-JAXB is only available out of the box with Java 8.
-If you use a more recent Java generation, add the following dependency to your project:
+You will need to ensure that the JAXB library is part of your project, for example by adding:
 
 [source,xml,indent=0,subs="verbatim"]
 ----