diff --git a/restful-notes-spring-hateoas/.gitignore b/restful-notes-spring-hateoas/.gitignore
new file mode 100644
index 0000000..5e3a83a
--- /dev/null
+++ b/restful-notes-spring-hateoas/.gitignore
@@ -0,0 +1,7 @@
+.classpath
+.gradle/
+.project
+.settings/
+bin/
+build/
+out/
diff --git a/restful-notes-spring-hateoas/README.md b/restful-notes-spring-hateoas/README.md
new file mode 100644
index 0000000..3a8b985
--- /dev/null
+++ b/restful-notes-spring-hateoas/README.md
@@ -0,0 +1,17 @@
+# Restful Notes Spring Hateoas Sample
+A RESTful web service for creating and storing notes.
+It uses hypermedia to describe the relationships between resources and to allow navigation between them.
+Demonstrates using Spring REST Docs with MockMvc and Spring HATEOAS.
+
+
+
+## Building and Running the Sample
+You will need Java 17 to build and run the sample.
+It is build using Gradle:
+
+```
+./gradlew build
+```
+
+As part of the build, files named `build/docs/asciidoc/api-guide.html` and `build/docs/asciidoc/getting-started-guide.html` are created.
+They are produced using Asciidoctor and include snippets generated by the sample's tests using Spring REST Docs.
diff --git a/restful-notes-spring-hateoas/build.gradle b/restful-notes-spring-hateoas/build.gradle
new file mode 100644
index 0000000..1f44075
--- /dev/null
+++ b/restful-notes-spring-hateoas/build.gradle
@@ -0,0 +1,57 @@
+plugins {
+	id "java"
+	id "org.asciidoctor.jvm.convert" version "3.3.2"
+	id "org.springframework.boot" version "3.0.0-M4"
+}
+
+apply plugin: 'io.spring.dependency-management'
+
+repositories {
+	maven { url 'https://repo.spring.io/milestone' }
+	mavenCentral()
+}
+
+group = 'com.example'
+
+sourceCompatibility = 17
+targetCompatibility = 17
+
+ext {
+	snippetsDir = file('build/generated-snippets')
+}
+
+configurations {
+	asciidoctorExtensions
+}
+
+dependencies {
+	asciidoctorExtensions 'org.springframework.restdocs:spring-restdocs-asciidoctor'
+
+	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+	implementation 'org.springframework.boot:spring-boot-starter-hateoas'
+	implementation 'org.springframework.boot:spring-boot-starter-validation'
+
+	runtimeOnly 'com.h2database:h2'
+	runtimeOnly 'org.atteo:evo-inflector:1.3'
+
+	testImplementation 'org.springframework.boot:spring-boot-starter-test'
+	testImplementation 'org.springframework.restdocs:spring-restdocs-mockmvc'
+}
+
+test {
+	useJUnitPlatform()
+	outputs.dir snippetsDir
+}
+
+asciidoctor {
+	configurations "asciidoctorExtensions"
+	inputs.dir snippetsDir
+	dependsOn test
+}
+
+bootJar {
+	dependsOn asciidoctor
+	from ("${asciidoctor.outputDir}/html5") {
+		into 'static/docs'
+	}
+}
diff --git a/restful-notes-spring-hateoas/gradle/wrapper/.!33814!gradle-wrapper.jar b/restful-notes-spring-hateoas/gradle/wrapper/.!33814!gradle-wrapper.jar
new file mode 100644
index 0000000..000fc61
Binary files /dev/null and b/restful-notes-spring-hateoas/gradle/wrapper/.!33814!gradle-wrapper.jar differ
diff --git a/restful-notes-spring-hateoas/gradle/wrapper/gradle-wrapper.jar b/restful-notes-spring-hateoas/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..7454180
Binary files /dev/null and b/restful-notes-spring-hateoas/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/restful-notes-spring-hateoas/gradle/wrapper/gradle-wrapper.properties b/restful-notes-spring-hateoas/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..8049c68
--- /dev/null
+++ b/restful-notes-spring-hateoas/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/restful-notes-spring-hateoas/gradlew b/restful-notes-spring-hateoas/gradlew
new file mode 100755
index 0000000..1b6c787
--- /dev/null
+++ b/restful-notes-spring-hateoas/gradlew
@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/restful-notes-spring-hateoas/gradlew.bat b/restful-notes-spring-hateoas/gradlew.bat
new file mode 100644
index 0000000..107acd3
--- /dev/null
+++ b/restful-notes-spring-hateoas/gradlew.bat
@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/restful-notes-spring-hateoas/settings.gradle b/restful-notes-spring-hateoas/settings.gradle
new file mode 100644
index 0000000..b1e9ad5
--- /dev/null
+++ b/restful-notes-spring-hateoas/settings.gradle
@@ -0,0 +1,6 @@
+pluginManagement {
+	repositories {
+		gradlePluginPortal()
+		maven { url "https://repo.spring.io/milestone" }
+	}
+}
\ No newline at end of file
diff --git a/restful-notes-spring-hateoas/src/docs/asciidoc/api-guide.adoc b/restful-notes-spring-hateoas/src/docs/asciidoc/api-guide.adoc
new file mode 100644
index 0000000..9074589
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/docs/asciidoc/api-guide.adoc
@@ -0,0 +1,229 @@
+= RESTful Notes API Guide
+Andy Wilkinson;
+:doctype: book
+:icons: font
+:source-highlighter: highlightjs
+:toc: left
+:toclevels: 4
+:sectlinks:
+:operation-curl-request-title: Example request
+:operation-http-response-title: Example response
+
+[[overview]]
+= Overview
+
+[[overview_http_verbs]]
+== HTTP verbs
+
+RESTful notes tries to adhere as closely as possible to standard HTTP and REST conventions in its
+use of HTTP verbs.
+
+|===
+| Verb | Usage
+
+| `GET`
+| Used to retrieve a resource
+
+| `POST`
+| Used to create a new resource
+
+| `PATCH`
+| Used to update an existing resource, including partial updates
+
+| `DELETE`
+| Used to delete an existing resource
+|===
+
+[[overview_http_status_codes]]
+== HTTP status codes
+
+RESTful notes tries to adhere as closely as possible to standard HTTP and REST conventions in its
+use of HTTP status codes.
+
+|===
+| Status code | Usage
+
+| `200 OK`
+| The request completed successfully
+
+| `201 Created`
+| A new resource has been created successfully. The resource's URI is available from the response's
+`Location` header
+
+| `204 No Content`
+| An update to an existing resource has been applied successfully
+
+| `400 Bad Request`
+| The request was malformed. The response body will include an error providing further information
+
+| `404 Not Found`
+| The requested resource did not exist
+|===
+
+[[overview_headers]]
+== Headers
+
+Every response has the following header(s):
+
+include::{snippets}/headers-example/response-headers.adoc[]
+
+[[overview_errors]]
+== Errors
+
+Whenever an error response (status code >= 400) is returned, the body will contain a JSON object
+that describes the problem. The error object has the following structure:
+
+include::{snippets}/error-example/response-fields.adoc[]
+
+For example, a request that attempts to apply a non-existent tag to a note will produce a
+`400 Bad Request` response:
+
+include::{snippets}/error-example/http-response.adoc[]
+
+[[overview_hypermedia]]
+== Hypermedia
+
+RESTful Notes uses hypermedia and resources include links to other resources in their
+responses. Responses are in https://github.com/mikekelly/hal_specification[Hypertext
+Application Language (HAL)] format. Links can be found beneath the `_links` key. Users of
+the API should not create URIs themselves, instead they should use the above-described
+links to navigate from resource to resource.
+
+[[resources]]
+= Resources
+
+
+
+[[resources_index]]
+== Index
+
+The index provides the entry point into the service.
+
+
+
+[[resources_index_access]]
+=== Accessing the index
+
+A `GET` request is used to access the index
+
+operation::index-example[snippets='response-fields,http-response,links']
+
+
+
+[[resources_notes]]
+== Notes
+
+The Notes resources is used to create and list notes
+
+
+
+[[resources_notes_list]]
+=== Listing notes
+
+A `GET` request will list all of the service's notes.
+
+operation::notes-list-example[snippets='response-fields,curl-request,http-response']
+
+
+
+[[resources_notes_create]]
+=== Creating a note
+
+A `POST` request is used to create a note.
+
+operation::notes-create-example[snippets='request-fields,curl-request,http-response']
+
+
+
+[[resources_tags]]
+== Tags
+
+The Tags resource is used to create and list tags.
+
+
+
+[[resources_tags_list]]
+=== Listing tags
+
+A `GET` request will list all of the service's tags.
+
+operation::tags-list-example[snippets='response-fields,curl-request,http-response']
+
+
+
+[[resources_tags_create]]
+=== Creating a tag
+
+A `POST` request is used to create a note
+
+operation::tags-create-example[snippets='request-fields,curl-request,http-response']
+
+
+
+[[resources_note]]
+== Note
+
+The Note resource is used to retrieve, update, and delete individual notes
+
+
+
+[[resources_note_links]]
+=== Links
+
+include::{snippets}/note-get-example/links.adoc[]
+
+
+
+[[resources_note_retrieve]]
+=== Retrieve a note
+
+A `GET` request will retrieve the details of a note
+
+operation::note-get-example[snippets='response-fields,curl-request,http-response']
+
+
+
+[[resources_note_update]]
+=== Update a note
+
+A `PATCH` request is used to update a note
+
+==== Request structure
+
+include::{snippets}/note-update-example/request-fields.adoc[]
+
+To leave an attribute of a note unchanged, any of the above may be omitted from the request.
+
+operation::note-update-example[snippets='curl-request,http-response']
+
+
+
+[[resources_tag]]
+== Tag
+
+The Tag resource is used to retrieve, update, and delete individual tags
+
+
+
+[[resources_tag_links]]
+=== Links
+
+include::{snippets}/tag-get-example/links.adoc[]
+
+
+
+[[resources_tag_retrieve]]
+=== Retrieve a tag
+
+A `GET` request will retrieve the details of a tag
+
+operation::tag-get-example[snippets='response-fields,curl-request,http-response']
+
+
+
+[[resources_tag_update]]
+=== Update a tag
+
+A `PATCH` request is used to update a tag
+
+operation::tag-update-example[snippets='request-fields,curl-request,http-response']
diff --git a/restful-notes-spring-hateoas/src/docs/asciidoc/getting-started-guide.adoc b/restful-notes-spring-hateoas/src/docs/asciidoc/getting-started-guide.adoc
new file mode 100644
index 0000000..7e8346a
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/docs/asciidoc/getting-started-guide.adoc
@@ -0,0 +1,173 @@
+= RESTful Notes Getting Started Guide
+Andy Wilkinson;
+:doctype: book
+:icons: font
+:source-highlighter: highlightjs
+:toc: left
+:toclevels: 4
+:sectlinks:
+
+[[introduction]]
+= Introduction
+
+RESTful Notes is a RESTful web service for creating and storing notes. It uses hypermedia
+to describe the relationships between resources and to allow navigation between them.
+
+
+
+[[getting_started_running_the_service]]
+== Running the service
+RESTful Notes is written using https://projects.spring.io/spring-boot[Spring Boot] which
+makes it easy to get it up and running so that you can start exploring the REST API.
+
+The first step is to clone the Git repository:
+
+[source,bash]
+----
+$ git clone https://github.com/spring-projects/spring-restdocs
+----
+
+Once the clone is complete, you're ready to get the service up and running:
+
+[source,bash]
+----
+$ cd samples/rest-notes-spring-hateoas
+$ ./gradlew build
+$ java -jar build/libs/*.jar
+----
+
+You can check that the service is up and running by executing a simple request using
+cURL:
+
+include::{snippets}/index/1/curl-request.adoc[]
+
+This request should yield the following response:
+
+include::{snippets}/index/1/http-response.adoc[]
+
+Note the `_links` in the JSON response. They are key to navigating the API.
+
+
+
+[[getting_started_creating_a_note]]
+== Creating a note
+Now that you've started the service and verified that it works, the next step is to use
+it to create a new note. As you saw above, the URI for working with notes is included as
+a link when you perform a `GET` request against the root of the service:
+
+include::{snippets}/index/1/http-response.adoc[]
+
+To create a note you need to execute a `POST` request to this URI, including a JSON
+payload containing the title and body of the note:
+
+include::{snippets}/creating-a-note/1/curl-request.adoc[]
+
+The response from this request should have a status code of `201 Created` and contain a
+`Location` header whose value is the URI of the newly created note:
+
+include::{snippets}/creating-a-note/1/http-response.adoc[]
+
+To work with the newly created note you use the URI in the `Location` header. For example
+you can access the note's details by performing a `GET` request:
+
+include::{snippets}/creating-a-note/2/curl-request.adoc[]
+
+This request will produce a response with the note's details in its body:
+
+include::{snippets}/creating-a-note/2/http-response.adoc[]
+
+Note the `note-tags` link which we'll make use of later.
+
+
+
+[[getting_started_creating_a_tag]]
+== Creating a tag
+To make a note easier to find, it can be associated with any number of tags. To be able
+to tag a note, you must first create the tag.
+
+Referring back to the response for the service's index, the URI for working with tags is
+include as a link:
+
+include::{snippets}/index/1/http-response.adoc[]
+
+To create a tag you need to execute a `POST` request to this URI, including a JSON
+payload containing the name of the tag:
+
+include::{snippets}/creating-a-note/3/curl-request.adoc[]
+
+The response from this request should have a status code of `201 Created` and contain a
+`Location` header whose value is the URI of the newly created tag:
+
+include::{snippets}/creating-a-note/3/http-response.adoc[]
+
+To work with the newly created tag you use the URI in the `Location` header. For example
+you can access the tag's details by performing a `GET` request:
+
+include::{snippets}/creating-a-note/4/curl-request.adoc[]
+
+This request will produce a response with the tag's details in its body:
+
+include::{snippets}/creating-a-note/4/http-response.adoc[]
+
+
+
+[[getting_started_tagging_a_note]]
+== Tagging a note
+A tag isn't particularly useful until it's been associated with one or more notes. There
+are two ways to tag a note: when the note is first created or by updating an existing
+note. We'll look at both of these in turn.
+
+
+
+[[getting_started_tagging_a_note_creating]]
+=== Creating a tagged note
+The process is largely the same as we saw before, but this time, in addition to providing
+a title and body for the note, we'll also provide the tag that we want to be associated
+with it.
+
+Once again we execute a `POST` request, but this time, in an array named tags, we include
+the URI of the tag we just created:
+
+include::{snippets}/creating-a-note/5/curl-request.adoc[]
+
+Once again, the response's `Location` header tells use the URI of the newly created note:
+
+include::{snippets}/creating-a-note/5/http-response.adoc[]
+
+As before, a `GET` request executed against this URI will retrieve the note's details:
+
+include::{snippets}/creating-a-note/6/curl-request.adoc[]
+include::{snippets}/creating-a-note/6/http-response.adoc[]
+
+To see the note's tags, execute a `GET` request against the URI of the note's
+`note-tags` link:
+
+include::{snippets}/creating-a-note/7/curl-request.adoc[]
+
+The response shows that, as expected, the note has a single tag:
+
+include::{snippets}/creating-a-note/7/http-response.adoc[]
+
+
+
+[[getting_started_tagging_a_note_existing]]
+=== Tagging an existing note
+An existing note can be tagged by executing a `PATCH` request against the note's URI with
+a body that contains the array of tags to be associated with the note. We'll use the
+URI of the untagged note that we created earlier:
+
+include::{snippets}/creating-a-note/8/curl-request.adoc[]
+
+This request should produce a `204 No Content` response:
+
+include::{snippets}/creating-a-note/8/http-response.adoc[]
+
+When we first created this note, we noted the `note-tags` link included in its details:
+
+include::{snippets}/creating-a-note/2/http-response.adoc[]
+
+We can use that link now and execute a `GET` request to see that the note now has a
+single tag:
+
+include::{snippets}/creating-a-note/9/curl-request.adoc[]
+include::{snippets}/creating-a-note/9/http-response.adoc[]
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/ExceptionSupressingErrorAttributes.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/ExceptionSupressingErrorAttributes.java
new file mode 100644
index 0000000..3f06485
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/ExceptionSupressingErrorAttributes.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.util.Map;
+
+import org.springframework.boot.web.error.ErrorAttributeOptions;
+import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;
+import org.springframework.stereotype.Component;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.WebRequest;
+
+@Component
+class ExceptionSupressingErrorAttributes extends DefaultErrorAttributes {
+
+	@Override
+	public Map<String, Object> getErrorAttributes(WebRequest webRequest,
+			ErrorAttributeOptions options) {
+		Map<String, Object> errorAttributes = super.getErrorAttributes(webRequest, options);
+		errorAttributes.remove("exception");
+		Object message = webRequest.getAttribute("javax.servlet.error.message", RequestAttributes.SCOPE_REQUEST);
+		if (message != null) {
+			errorAttributes.put("message", message);
+		}
+		return errorAttributes;
+	}
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/IndexController.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/IndexController.java
new file mode 100644
index 0000000..aba9f11
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/IndexController.java
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.linkTo;
+
+import org.springframework.hateoas.RepresentationModel;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/")
+class IndexController {
+
+	@RequestMapping(method=RequestMethod.GET)
+	public RepresentationModel<?> index() {
+		RepresentationModel<?> index = new RepresentationModel<>();
+		index.add(linkTo(NotesController.class).withRel("notes"));
+		index.add(linkTo(TagsController.class).withRel("tags"));
+		return index;
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/Note.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/Note.java
new file mode 100644
index 0000000..41ce6c5
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/Note.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.util.List;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToMany;
+
+@Entity
+public class Note {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.AUTO)
+	private long id;
+
+	private String title;
+
+	private String body;
+
+	@ManyToMany
+	private List<Tag> tags;
+
+	public long getId() {
+		return id;
+	}
+
+	public void setId(long id) {
+		this.id = id;
+	}
+
+	public String getTitle() {
+		return title;
+	}
+
+	public void setTitle(String title) {
+		this.title = title;
+	}
+
+	public String getBody() {
+		return body;
+	}
+
+	public void setBody(String body) {
+		this.body = body;
+	}
+
+	public List<Tag> getTags() {
+		return tags;
+	}
+
+	public void setTags(List<Tag> tags) {
+		this.tags = tags;
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteInput.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteInput.java
new file mode 100644
index 0000000..c1792ba
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteInput.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.net.URI;
+import java.util.Collections;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import jakarta.validation.constraints.NotBlank;
+
+class NoteInput {
+
+	@NotBlank
+	private final String title;
+
+	private final String body;
+
+	private final List<URI> tagUris;
+
+	@JsonCreator
+	NoteInput(@JsonProperty("title") String title,
+			@JsonProperty("body") String body, @JsonProperty("tags") List<URI> tagUris) {
+		this.title = title;
+		this.body = body;
+		this.tagUris = tagUris == null ? Collections.<URI>emptyList() : tagUris;
+	}
+
+	String getTitle() {
+		return title;
+	}
+
+	String getBody() {
+		return body;
+	}
+
+	@JsonProperty("tags")
+	List<URI> getTagUris() {
+		return this.tagUris;
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/NotePatchInput.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NotePatchInput.java
new file mode 100644
index 0000000..284b6dd
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NotePatchInput.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.net.URI;
+import java.util.Collections;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+class NotePatchInput {
+	
+	@NullOrNotBlank 
+	private final String title;
+	
+	private final String body;
+	
+	private final List<URI> tagUris;
+
+	@JsonCreator
+	NotePatchInput(@JsonProperty("title") String title,
+			@JsonProperty("body") String body, @JsonProperty("tags") List<URI> tagUris) {
+		this.title = title;
+		this.body = body;
+		this.tagUris = tagUris == null ? Collections.<URI>emptyList() : tagUris;
+	}
+	
+	String getTitle() {
+		return title;
+	}
+
+	String getBody() {
+		return body;
+	}
+
+	@JsonProperty("tags")
+	List<URI> getTagUris() {
+		return this.tagUris;
+	}
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteRepository.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteRepository.java
new file mode 100644
index 0000000..8e64ec6
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteRepository.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.util.Collection;
+import java.util.List;
+
+import org.springframework.data.repository.CrudRepository;
+
+interface NoteRepository extends CrudRepository<Note, Long> {
+
+	Note findById(long id);
+
+	List<Note> findByTagsIn(Collection<Tag> tags);
+	
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteRepresentationModelAssembler.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteRepresentationModelAssembler.java
new file mode 100644
index 0000000..11f69f0
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NoteRepresentationModelAssembler.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.linkTo;
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.methodOn;
+
+import org.springframework.hateoas.RepresentationModel;
+import org.springframework.hateoas.server.core.Relation;
+import org.springframework.hateoas.server.mvc.RepresentationModelAssemblerSupport;
+import org.springframework.stereotype.Component;
+
+import com.example.notes.NoteRepresentationModelAssembler.NoteModel;
+
+@Component
+class NoteRepresentationModelAssembler extends RepresentationModelAssemblerSupport<Note, NoteModel> {
+
+	NoteRepresentationModelAssembler() {
+		super(NotesController.class, NoteModel.class);
+	}
+
+	@Override
+	public NoteModel toModel(Note entity) {
+		NoteModel noteModel = createModelWithId(entity.getId(), entity);
+		noteModel.add(linkTo(methodOn(NotesController.class).noteTags(entity.getId())).withRel("note-tags"));
+		return noteModel;
+	}
+	
+	@Override
+	protected NoteModel instantiateModel(Note entity) {
+		return new NoteModel(entity);
+	}
+
+	@Relation(collectionRelation = "notes", itemRelation = "note")
+	static class NoteModel extends RepresentationModel<NoteModel> {
+		
+		private final Note note;
+
+		NoteModel(Note note) {
+			this.note = note;
+		}
+		
+		public String getTitle() {
+			return this.note.getTitle();
+		}
+		
+		public String getBody() {
+			return this.note.getBody();
+		}
+		
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/NotesController.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NotesController.java
new file mode 100644
index 0000000..c2dec81
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NotesController.java
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.linkTo;
+
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.hateoas.CollectionModel;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.util.UriTemplate;
+
+import com.example.notes.NoteRepresentationModelAssembler.NoteModel;
+import com.example.notes.TagRepresentationModelAssembler.TagModel;
+
+@RestController
+@RequestMapping("/notes")
+class NotesController {
+
+	private static final UriTemplate TAG_URI_TEMPLATE = new UriTemplate("/tags/{id}");
+
+	private final NoteRepository noteRepository;
+
+	private final TagRepository tagRepository;
+	
+	private final NoteRepresentationModelAssembler noteAssembler;
+	
+	private final TagRepresentationModelAssembler tagAssembler;
+
+	NotesController(NoteRepository noteRepository, TagRepository tagRepository,
+			NoteRepresentationModelAssembler noteAssembler, TagRepresentationModelAssembler tagAssembler) {
+		this.noteRepository = noteRepository;
+		this.tagRepository = tagRepository;
+		this.noteAssembler = noteAssembler;
+		this.tagAssembler = tagAssembler;
+	}
+
+	@RequestMapping(method = RequestMethod.GET)
+	CollectionModel<NoteModel> all() {
+		return noteAssembler.toCollectionModel(this.noteRepository.findAll());
+	}
+
+	@ResponseStatus(HttpStatus.CREATED)
+	@RequestMapping(method = RequestMethod.POST)
+	HttpHeaders create(@RequestBody NoteInput noteInput) {
+		Note note = new Note();
+		note.setTitle(noteInput.getTitle());
+		note.setBody(noteInput.getBody());
+		note.setTags(getTags(noteInput.getTagUris()));
+
+		this.noteRepository.save(note);
+
+		HttpHeaders httpHeaders = new HttpHeaders();
+		httpHeaders
+				.setLocation(linkTo(NotesController.class).slash(note.getId()).toUri());
+
+		return httpHeaders;
+	}
+
+	@RequestMapping(value = "/{id}", method = RequestMethod.DELETE)
+	void delete(@PathVariable("id") long id) {
+		this.noteRepository.deleteById(id);
+	}
+
+	@RequestMapping(value = "/{id}", method = RequestMethod.GET)
+	NoteModel note(@PathVariable("id") long id) {
+		return this.noteAssembler.toModel(findNoteById(id));
+	}
+
+	@RequestMapping(value = "/{id}/tags", method = RequestMethod.GET)
+	CollectionModel<TagModel> noteTags(@PathVariable("id") long id) {
+		return this.tagAssembler.toCollectionModel(findNoteById(id).getTags());
+	}
+
+	@RequestMapping(value = "/{id}", method = RequestMethod.PATCH)
+	@ResponseStatus(HttpStatus.NO_CONTENT)
+	void updateNote(@PathVariable("id") long id, @RequestBody NotePatchInput noteInput) {
+		Note note = findNoteById(id);
+		if (noteInput.getTagUris() != null) {
+			note.setTags(getTags(noteInput.getTagUris()));
+		}
+		if (noteInput.getTitle() != null) {
+			note.setTitle(noteInput.getTitle());
+		}
+		if (noteInput.getBody() != null) {
+			note.setBody(noteInput.getBody());
+		}
+		this.noteRepository.save(note);
+	}
+
+	private Note findNoteById(long id) {
+		Note note = this.noteRepository.findById(id);
+		if (note == null) {
+			throw new ResourceDoesNotExistException();
+		}
+		return note;
+	}
+
+	private List<Tag> getTags(List<URI> tagLocations) {
+		List<Tag> tags = new ArrayList<>(tagLocations.size());
+		for (URI tagLocation: tagLocations) {
+			Tag tag = this.tagRepository.findById(extractTagId(tagLocation));
+			if (tag == null) {
+				throw new IllegalArgumentException("The tag '" + tagLocation
+										+ "' does not exist");
+			}
+			tags.add(tag);
+		}
+		return tags;
+	}
+
+	private long extractTagId(URI tagLocation) {
+		try {
+			String idString = TAG_URI_TEMPLATE.match(tagLocation.toASCIIString()).get(
+					"id");
+			return Long.valueOf(idString);
+		}
+		catch (RuntimeException ex) {
+			throw new IllegalArgumentException("The tag '" + tagLocation + "' is invalid");
+		}
+	}
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/NullOrNotBlank.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NullOrNotBlank.java
new file mode 100644
index 0000000..3dc16eb
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/NullOrNotBlank.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.hibernate.validator.constraints.CompositionType;
+import org.hibernate.validator.constraints.ConstraintComposition;
+
+import jakarta.validation.Constraint;
+import jakarta.validation.Payload;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Null;
+
+@ConstraintComposition(CompositionType.OR)
+@Constraint(validatedBy = {})
+@Null
+@NotBlank
+@Target({ ElementType.FIELD, ElementType.PARAMETER })
+@Retention(RetentionPolicy.RUNTIME)
+@interface NullOrNotBlank {
+
+	String message() default "Must be null or not blank";
+
+	Class<?>[] groups() default {};
+
+	Class<? extends Payload>[] payload() default {};
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/ResourceDoesNotExistException.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/ResourceDoesNotExistException.java
new file mode 100644
index 0000000..410b909
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/ResourceDoesNotExistException.java
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+@SuppressWarnings("serial")
+class ResourceDoesNotExistException extends RuntimeException {
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/RestNotesControllerAdvice.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/RestNotesControllerAdvice.java
new file mode 100644
index 0000000..4349091
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/RestNotesControllerAdvice.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.io.IOException;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+@ControllerAdvice
+class RestNotesControllerAdvice {
+
+	@ExceptionHandler(IllegalArgumentException.class)
+	void handleIllegalArgumentException(IllegalArgumentException ex,
+			HttpServletResponse response) throws IOException {
+		response.sendError(HttpStatus.BAD_REQUEST.value(), ex.getMessage());
+	}
+
+	@ExceptionHandler(ResourceDoesNotExistException.class)
+	void handleResourceDoesNotExistException(ResourceDoesNotExistException ex,
+			HttpServletRequest request, HttpServletResponse response) throws IOException {
+		response.sendError(HttpStatus.NOT_FOUND.value(),
+				"The resource '" + request.getRequestURI() + "' does not exist");
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/RestNotesSpringHateoas.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/RestNotesSpringHateoas.java
new file mode 100644
index 0000000..506084f
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/RestNotesSpringHateoas.java
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+class RestNotesSpringHateoas {
+
+	public static void main(String[] args) {
+		SpringApplication.run(RestNotesSpringHateoas.class, args);
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/Tag.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/Tag.java
new file mode 100644
index 0000000..66b18a5
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/Tag.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import java.util.List;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToMany;
+
+@Entity
+public class Tag {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.AUTO)
+	private long id;
+
+	private String name;
+
+	@ManyToMany(mappedBy = "tags")
+	private List<Note> notes;
+
+	public long getId() {
+		return id;
+	}
+
+	public void setId(long id) {
+		this.id = id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public List<Note> getNotes() {
+		return notes;
+	}
+
+	public void setNotes(List<Note> notes) {
+		this.notes = notes;
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagInput.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagInput.java
new file mode 100644
index 0000000..fb7e90f
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagInput.java
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import jakarta.validation.constraints.NotBlank;
+
+class TagInput {
+
+	@NotBlank
+	private final String name;
+
+	@JsonCreator
+	TagInput(@NotBlank @JsonProperty("name") String name) {
+		this.name = name;
+	}
+
+	String getName() {
+		return name;
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagPatchInput.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagPatchInput.java
new file mode 100644
index 0000000..a851d92
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagPatchInput.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+class TagPatchInput {
+	
+	@NullOrNotBlank
+	private final String name;
+
+	@JsonCreator
+	TagPatchInput(@NullOrNotBlank @JsonProperty("name") String name) {
+		this.name = name;
+	}
+
+	String getName() {
+		return name;
+	}
+	
+}
\ No newline at end of file
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagRepository.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagRepository.java
new file mode 100644
index 0000000..8e67906
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagRepository.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import org.springframework.data.repository.CrudRepository;
+
+interface TagRepository extends CrudRepository<Tag, Long> {
+
+	Tag findById(long id);
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagRepresentationModelAssembler.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagRepresentationModelAssembler.java
new file mode 100644
index 0000000..592f3c4
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagRepresentationModelAssembler.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.linkTo;
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.methodOn;
+
+import org.springframework.hateoas.RepresentationModel;
+import org.springframework.hateoas.server.core.Relation;
+import org.springframework.hateoas.server.mvc.RepresentationModelAssemblerSupport;
+import org.springframework.stereotype.Component;
+
+import com.example.notes.TagRepresentationModelAssembler.TagModel;
+
+@Component
+class TagRepresentationModelAssembler extends RepresentationModelAssemblerSupport<Tag, TagModel> {
+
+	TagRepresentationModelAssembler() {
+		super(TagsController.class, TagModel.class);
+	}
+
+	@Override
+	public TagModel toModel(Tag entity) {
+		TagModel model = new TagModel(entity);
+		model.add(linkTo(methodOn(TagsController.class).tag(entity.getId())).withSelfRel(),
+			linkTo(methodOn(TagsController.class).tagNotes(entity.getId())).withRel("tagged-notes"));
+		return model;
+	}
+	
+	@Override
+	protected TagModel instantiateModel(Tag entity) {
+		return new TagModel(entity);
+	}
+
+	@Relation(collectionRelation = "tags", itemRelation = "tag")
+	static class TagModel extends RepresentationModel<TagModel> {
+		
+		private final Tag tag;
+		
+		TagModel(Tag tag) {
+			this.tag = tag;
+		}
+		
+		public String getName() {
+			return this.tag.getName();
+		}
+		
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagsController.java b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagsController.java
new file mode 100644
index 0000000..12791bb
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/java/com/example/notes/TagsController.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.linkTo;
+
+import org.springframework.hateoas.CollectionModel;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.example.notes.NoteRepresentationModelAssembler.NoteModel;
+import com.example.notes.TagRepresentationModelAssembler.TagModel;
+
+@RestController
+@RequestMapping("tags")
+class TagsController {
+
+	private final TagRepository repository;
+	
+	private final TagRepresentationModelAssembler tagAssembler;
+	
+	private final NoteRepresentationModelAssembler noteAssembler;
+
+	TagsController(TagRepository repository, TagRepresentationModelAssembler tagAssembler,
+			NoteRepresentationModelAssembler noteAssembler) {
+		this.repository = repository;
+		this.tagAssembler = tagAssembler;
+		this.noteAssembler = noteAssembler;
+	}
+
+	@RequestMapping(method = RequestMethod.GET)
+	CollectionModel<TagModel> all() {
+		return this.tagAssembler.toCollectionModel(this.repository.findAll());
+	}
+
+	@ResponseStatus(HttpStatus.CREATED)
+	@RequestMapping(method = RequestMethod.POST)
+	HttpHeaders create(@RequestBody TagInput tagInput) {
+		Tag tag = new Tag();
+		tag.setName(tagInput.getName());
+
+		this.repository.save(tag);
+
+		HttpHeaders httpHeaders = new HttpHeaders();
+		httpHeaders.setLocation(linkTo(TagsController.class).slash(tag.getId()).toUri());
+
+		return httpHeaders;
+	}
+
+	@RequestMapping(value = "/{id}", method = RequestMethod.DELETE)
+	void delete(@PathVariable("id") long id) {
+		this.repository.deleteById(id);
+	}
+
+	@RequestMapping(value = "/{id}", method = RequestMethod.GET)
+	TagModel tag(@PathVariable("id") long id) {
+		return this.tagAssembler.toModel(findTagById(id));
+	}
+
+	@RequestMapping(value = "/{id}/notes", method = RequestMethod.GET)
+	CollectionModel<NoteModel> tagNotes(@PathVariable("id") long id) {
+		return this.noteAssembler.toCollectionModel(findTagById(id).getNotes());
+	}
+
+	private Tag findTagById(long id) {
+		Tag tag = this.repository.findById(id);
+		if (tag == null) {
+			throw new ResourceDoesNotExistException();
+		}
+		return tag;
+	}
+
+	@RequestMapping(value = "/{id}", method = RequestMethod.PATCH)
+	@ResponseStatus(HttpStatus.NO_CONTENT)
+	void updateTag(@PathVariable("id") long id, @RequestBody TagPatchInput tagInput) {
+		Tag tag = findTagById(id);
+		if (tagInput.getName() != null) {
+			tag.setName(tagInput.getName());
+		}
+		this.repository.save(tag);
+	}
+}
diff --git a/restful-notes-spring-hateoas/src/main/resources/application.properties b/restful-notes-spring-hateoas/src/main/resources/application.properties
new file mode 100644
index 0000000..c94d3e7
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/main/resources/application.properties
@@ -0,0 +1 @@
+server.error.include-message=always
\ No newline at end of file
diff --git a/restful-notes-spring-hateoas/src/test/java/com/example/notes/ApiDocumentation.java b/restful-notes-spring-hateoas/src/test/java/com/example/notes/ApiDocumentation.java
new file mode 100644
index 0000000..022ca5d
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/test/java/com/example/notes/ApiDocumentation.java
@@ -0,0 +1,402 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.springframework.restdocs.headers.HeaderDocumentation.headerWithName;
+import static org.springframework.restdocs.headers.HeaderDocumentation.responseHeaders;
+import static org.springframework.restdocs.hypermedia.HypermediaDocumentation.linkWithRel;
+import static org.springframework.restdocs.hypermedia.HypermediaDocumentation.links;
+import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.document;
+import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.documentationConfiguration;
+import static org.springframework.restdocs.mockmvc.RestDocumentationRequestBuilders.get;
+import static org.springframework.restdocs.mockmvc.RestDocumentationRequestBuilders.patch;
+import static org.springframework.restdocs.mockmvc.RestDocumentationRequestBuilders.post;
+import static org.springframework.restdocs.operation.preprocess.Preprocessors.preprocessRequest;
+import static org.springframework.restdocs.operation.preprocess.Preprocessors.preprocessResponse;
+import static org.springframework.restdocs.operation.preprocess.Preprocessors.prettyPrint;
+import static org.springframework.restdocs.payload.PayloadDocumentation.fieldWithPath;
+import static org.springframework.restdocs.payload.PayloadDocumentation.requestFields;
+import static org.springframework.restdocs.payload.PayloadDocumentation.responseFields;
+import static org.springframework.restdocs.payload.PayloadDocumentation.subsectionWithPath;
+import static org.springframework.restdocs.snippet.Attributes.key;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.hateoas.MediaTypes;
+import org.springframework.restdocs.RestDocumentationContextProvider;
+import org.springframework.restdocs.RestDocumentationExtension;
+import org.springframework.restdocs.constraints.ConstraintDescriptions;
+import org.springframework.restdocs.mockmvc.RestDocumentationResultHandler;
+import org.springframework.restdocs.payload.FieldDescriptor;
+import org.springframework.restdocs.payload.JsonFieldType;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.util.StringUtils;
+import org.springframework.web.context.WebApplicationContext;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import jakarta.servlet.RequestDispatcher;
+
+@SpringBootTest
+@ExtendWith(RestDocumentationExtension.class)
+public class ApiDocumentation {
+
+
+	private RestDocumentationResultHandler documentationHandler;
+
+	@Autowired
+	private NoteRepository noteRepository;
+
+	@Autowired
+	private TagRepository tagRepository;
+
+	@Autowired
+	private ObjectMapper objectMapper;
+
+	@Autowired
+	private WebApplicationContext context;
+
+	private MockMvc mockMvc;
+
+	@BeforeEach
+	void setUp(RestDocumentationContextProvider restDocumentation) {
+		this.documentationHandler = document("{method-name}",
+			preprocessRequest(prettyPrint()),
+			preprocessResponse(prettyPrint()));
+
+		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
+			.apply(documentationConfiguration(restDocumentation))
+			.alwaysDo(this.documentationHandler)
+			.build();
+	}
+
+	@Test
+	void headersExample() throws Exception {
+		this.mockMvc
+			.perform(get("/"))
+			.andExpect(status().isOk())
+			.andDo(this.documentationHandler.document(
+				responseHeaders(
+					headerWithName("Content-Type").description("The Content-Type of the payload, e.g. `application/hal+json`"))));
+	}
+
+	@Test
+	void errorExample() throws Exception {
+		this.mockMvc
+			.perform(get("/error")
+				.requestAttr(RequestDispatcher.ERROR_STATUS_CODE, 400)
+				.requestAttr(RequestDispatcher.ERROR_REQUEST_URI, "/notes")
+				.requestAttr(RequestDispatcher.ERROR_MESSAGE, "The tag 'http://localhost:8080/tags/123' does not exist"))
+			.andExpect(status().isBadRequest())
+			.andExpect(jsonPath("error", is("Bad Request")))
+			.andExpect(jsonPath("timestamp", is(notNullValue())))
+			.andExpect(jsonPath("status", is(400)))
+			.andExpect(jsonPath("path", is(notNullValue())))
+			.andDo(this.documentationHandler.document(
+				responseFields(
+					fieldWithPath("error").description("The HTTP error that occurred, e.g. `Bad Request`"),
+					fieldWithPath("message").description("A description of the cause of the error"),
+					fieldWithPath("path").description("The path to which the request was made"),
+					fieldWithPath("status").description("The HTTP status code, e.g. `400`"),
+					fieldWithPath("timestamp").description("The time, in milliseconds, at which the error occurred"))));
+	}
+
+	@Test
+	void indexExample() throws Exception {
+		this.mockMvc.perform(get("/"))
+			.andExpect(status().isOk())
+			.andDo(this.documentationHandler.document(
+				links(
+					linkWithRel("notes").description("The <<resources_notes,Notes resource>>"),
+					linkWithRel("tags").description("The <<resources_tags,Tags resource>>")),
+				responseFields(
+					subsectionWithPath("_links").description("<<resources_index_access_links,Links>> to other resources"))));
+	}
+
+	@Test
+	void notesListExample() throws Exception {
+		this.noteRepository.deleteAll();
+
+		createNote("REST maturity model", "https://martinfowler.com/articles/richardsonMaturityModel.html");
+		createNote("Hypertext Application Language (HAL)", "https://github.com/mikekelly/hal_specification");
+		createNote("Application-Level Profile Semantics (ALPS)", "https://github.com/alps-io/spec");
+
+		this.mockMvc
+			.perform(get("/notes"))
+			.andExpect(status().isOk())
+			.andDo(this.documentationHandler.document(
+				responseFields(
+					subsectionWithPath("_embedded.notes").description("An array of <<resources_note, Note resources>>"))));
+	}
+
+	@Test
+	void notesCreateExample() throws Exception {
+		Map<String, String> tag = new HashMap<String, String>();
+		tag.put("name", "REST");
+
+		String tagLocation = this.mockMvc
+			.perform(post("/tags")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(tag)))
+			.andExpect(status().isCreated())
+			.andReturn().getResponse().getHeader("Location");
+
+		Map<String, Object> note = new HashMap<String, Object>();
+		note.put("title", "REST maturity model");
+		note.put("body", "https://martinfowler.com/articles/richardsonMaturityModel.html");
+		note.put("tags", Arrays.asList(tagLocation));
+
+		ConstrainedFields fields = new ConstrainedFields(NoteInput.class);
+
+		this.mockMvc
+			.perform(post("/notes")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(note)))
+			.andExpect(
+				status().isCreated())
+			.andDo(this.documentationHandler.document(
+				requestFields(
+					fields.withPath("title").description("The title of the note"),
+					fields.withPath("body").description("The body of the note"),
+					fields.withPath("tags").description("An array of tag resource URIs"))));
+	}
+
+	@Test
+	void noteGetExample() throws Exception {
+		Map<String, String> tag = new HashMap<String, String>();
+		tag.put("name", "REST");
+
+		String tagLocation = this.mockMvc
+			.perform(post("/tags")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(tag)))
+			.andExpect(status().isCreated())
+			.andReturn().getResponse().getHeader("Location");
+
+		Map<String, Object> note = new HashMap<String, Object>();
+		note.put("title", "REST maturity model");
+		note.put("body", "https://martinfowler.com/articles/richardsonMaturityModel.html");
+		note.put("tags", Arrays.asList(tagLocation));
+
+		String noteLocation = this.mockMvc
+			.perform(post("/notes")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(note)))
+			.andExpect(status().isCreated())
+			.andReturn().getResponse().getHeader("Location");
+
+		this.mockMvc
+			.perform(get(noteLocation))
+			.andExpect(status().isOk())
+			.andExpect(jsonPath("title", is(note.get("title"))))
+			.andExpect(jsonPath("body", is(note.get("body"))))
+			.andExpect(jsonPath("_links.self.href", is(noteLocation)))
+			.andExpect(jsonPath("_links.note-tags", is(notNullValue())))
+			.andDo(this.documentationHandler.document(
+				links(
+					linkWithRel("self").description("This <<resources_note,note>>"),
+					linkWithRel("note-tags").description("This note's tags")),
+				responseFields(
+					fieldWithPath("title").description("The title of the note"),
+					fieldWithPath("body").description("The body of the note"),
+					subsectionWithPath("_links").description("<<resources_note_links,Links>> to other resources"))));
+
+	}
+
+	@Test
+	void tagsListExample() throws Exception {
+		this.noteRepository.deleteAll();
+		this.tagRepository.deleteAll();
+
+		createTag("REST");
+		createTag("Hypermedia");
+		createTag("HTTP");
+
+		this.mockMvc
+			.perform(get("/tags"))
+			.andExpect(status().isOk())
+			.andDo(this.documentationHandler.document(
+				responseFields(
+					subsectionWithPath("_embedded.tags").description("An array of <<resources_tag,Tag resources>>"))));
+	}
+
+	@Test
+	void tagsCreateExample() throws Exception {
+		Map<String, String> tag = new HashMap<String, String>();
+		tag.put("name", "REST");
+
+		ConstrainedFields fields = new ConstrainedFields(TagInput.class);
+
+		this.mockMvc
+			.perform(post("/tags")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(tag)))
+			.andExpect(status().isCreated())
+			.andDo(this.documentationHandler.document(
+				requestFields(
+					fields.withPath("name").description("The name of the tag"))));
+	}
+
+	@Test
+	void noteUpdateExample() throws Exception {
+		Map<String, Object> note = new HashMap<String, Object>();
+		note.put("title", "REST maturity model");
+		note.put("body", "https://martinfowler.com/articles/richardsonMaturityModel.html");
+
+		String noteLocation = this.mockMvc
+			.perform(post("/notes")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(note)))
+			.andExpect(status().isCreated())
+			.andReturn().getResponse().getHeader("Location");
+
+		this.mockMvc
+			.perform(get(noteLocation))
+			.andExpect(status().isOk())
+			.andExpect(jsonPath("title", is(note.get("title"))))
+			.andExpect(jsonPath("body", is(note.get("body"))))
+			.andExpect(jsonPath("_links.self.href", is(noteLocation)))
+			.andExpect(jsonPath("_links.note-tags", is(notNullValue())));
+
+		Map<String, String> tag = new HashMap<String, String>();
+		tag.put("name", "REST");
+
+		String tagLocation = this.mockMvc
+			.perform(post("/tags")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(tag)))
+			.andExpect(status().isCreated())
+			.andReturn().getResponse().getHeader("Location");
+
+		Map<String, Object> noteUpdate = new HashMap<String, Object>();
+		noteUpdate.put("tags", Arrays.asList(tagLocation));
+
+		ConstrainedFields fields = new ConstrainedFields(NotePatchInput.class);
+
+		this.mockMvc
+			.perform(patch(noteLocation)
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(noteUpdate)))
+			.andExpect(status().isNoContent())
+			.andDo(this.documentationHandler.document(
+				requestFields(
+					fields.withPath("title")
+						.description("The title of the note")
+						.type(JsonFieldType.STRING)
+						.optional(),
+					fields.withPath("body")
+						.description("The body of the note")
+						.type(JsonFieldType.STRING)
+						.optional(),
+					fields.withPath("tags")
+						.description("An array of tag resource URIs"))));
+	}
+
+	@Test
+	void tagGetExample() throws Exception {
+		Map<String, String> tag = new HashMap<String, String>();
+		tag.put("name", "REST");
+
+		String tagLocation = this.mockMvc
+			.perform(post("/tags")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(tag)))
+			.andExpect(status().isCreated())
+			.andReturn().getResponse().getHeader("Location");
+
+		this.mockMvc
+			.perform(get(tagLocation))
+			.andExpect(status().isOk())
+			.andExpect(jsonPath("name", is(tag.get("name"))))
+			.andDo(this.documentationHandler.document(
+				links(
+					linkWithRel("self").description("This <<resources_tag,tag>>"),
+					linkWithRel("tagged-notes").description("The notes that have this tag")),
+				responseFields(
+					fieldWithPath("name").description("The name of the tag"),
+					subsectionWithPath("_links").description("<<resources_tag_links,Links>> to other resources"))));
+	}
+
+	@Test
+	void tagUpdateExample() throws Exception {
+		Map<String, String> tag = new HashMap<String, String>();
+		tag.put("name", "REST");
+
+		String tagLocation = this.mockMvc
+			.perform(post("/tags")
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(tag)))
+			.andExpect(status().isCreated())
+			.andReturn().getResponse().getHeader("Location");
+
+		Map<String, Object> tagUpdate = new HashMap<String, Object>();
+		tagUpdate.put("name", "RESTful");
+
+		ConstrainedFields fields = new ConstrainedFields(TagPatchInput.class);
+
+		this.mockMvc
+			.perform(patch(tagLocation)
+				.contentType(MediaTypes.HAL_JSON)
+				.content(this.objectMapper.writeValueAsString(tagUpdate)))
+			.andExpect(status().isNoContent())
+			.andDo(this.documentationHandler.document(
+				requestFields(
+					fields.withPath("name").description("The name of the tag"))));
+	}
+
+	private void createNote(String title, String body) {
+		Note note = new Note();
+		note.setTitle(title);
+		note.setBody(body);
+
+		this.noteRepository.save(note);
+	}
+
+	private void createTag(String name) {
+		Tag tag = new Tag();
+		tag.setName(name);
+		this.tagRepository.save(tag);
+	}
+
+	private static class ConstrainedFields {
+
+		private final ConstraintDescriptions constraintDescriptions;
+
+		ConstrainedFields(Class<?> input) {
+			this.constraintDescriptions = new ConstraintDescriptions(input);
+		}
+
+		private FieldDescriptor withPath(String path) {
+			return fieldWithPath(path).attributes(key("constraints").value(StringUtils
+					.collectionToDelimitedString(this.constraintDescriptions
+							.descriptionsForProperty(path), ". ")));
+		}
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/test/java/com/example/notes/GettingStartedDocumentation.java b/restful-notes-spring-hateoas/src/test/java/com/example/notes/GettingStartedDocumentation.java
new file mode 100644
index 0000000..5203c2b
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/test/java/com/example/notes/GettingStartedDocumentation.java
@@ -0,0 +1,184 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.hamcrest.Matchers.hasSize;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.document;
+import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.documentationConfiguration;
+import static org.springframework.restdocs.mockmvc.RestDocumentationRequestBuilders.get;
+import static org.springframework.restdocs.mockmvc.RestDocumentationRequestBuilders.patch;
+import static org.springframework.restdocs.mockmvc.RestDocumentationRequestBuilders.post;
+import static org.springframework.restdocs.operation.preprocess.Preprocessors.preprocessRequest;
+import static org.springframework.restdocs.operation.preprocess.Preprocessors.preprocessResponse;
+import static org.springframework.restdocs.operation.preprocess.Preprocessors.prettyPrint;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.header;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import java.io.UnsupportedEncodingException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.hateoas.MediaTypes;
+import org.springframework.restdocs.RestDocumentationContextProvider;
+import org.springframework.restdocs.RestDocumentationExtension;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.MvcResult;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.context.WebApplicationContext;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.jayway.jsonpath.JsonPath;
+
+@SpringBootTest
+@ExtendWith(RestDocumentationExtension.class)
+public class GettingStartedDocumentation {
+
+	@Autowired
+	private ObjectMapper objectMapper;
+
+	@Autowired
+	private WebApplicationContext context;
+
+	private MockMvc mockMvc;
+
+	@BeforeEach
+	void setUp(RestDocumentationContextProvider restDocumentation) {
+		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
+				.apply(documentationConfiguration(restDocumentation))
+				.alwaysDo(document("{method-name}/{step}/",
+						preprocessRequest(prettyPrint()),
+						preprocessResponse(prettyPrint())))
+				.build();
+	}
+
+	@Test
+	void index() throws Exception {
+		this.mockMvc.perform(get("/").accept(MediaTypes.HAL_JSON))
+			.andExpect(status().isOk())
+			.andExpect(jsonPath("_links.notes", is(notNullValue())))
+			.andExpect(jsonPath("_links.tags", is(notNullValue())));
+	}
+
+	@Test
+	void creatingANote() throws JsonProcessingException, Exception {
+		String noteLocation = createNote();
+		MvcResult note = getNote(noteLocation);
+
+		String tagLocation = createTag();
+		getTag(tagLocation);
+
+		String taggedNoteLocation = createTaggedNote(tagLocation);
+		MvcResult taggedNote = getNote(taggedNoteLocation);
+		getTags(getLink(taggedNote, "note-tags"));
+
+		tagExistingNote(noteLocation, tagLocation);
+		getTags(getLink(note, "note-tags"));
+	}
+
+	private String createNote() throws Exception {
+		Map<String, String> note = new HashMap<String, String>();
+		note.put("title", "Note creation with cURL");
+		note.put("body", "An example of how to create a note using cURL");
+
+		String noteLocation = this.mockMvc
+				.perform(
+						post("/notes").contentType(MediaTypes.HAL_JSON).content(
+								objectMapper.writeValueAsString(note)))
+				.andExpect(status().isCreated())
+				.andExpect(header().string("Location", notNullValue()))
+				.andReturn().getResponse().getHeader("Location");
+		return noteLocation;
+	}
+
+	private MvcResult getNote(String noteLocation) throws Exception {
+		return this.mockMvc.perform(get(noteLocation))
+				.andExpect(status().isOk())
+				.andExpect(jsonPath("title", is(notNullValue())))
+				.andExpect(jsonPath("body", is(notNullValue())))
+				.andExpect(jsonPath("_links.note-tags", is(notNullValue())))
+				.andReturn();
+	}
+
+	private String createTag() throws Exception, JsonProcessingException {
+		Map<String, String> tag = new HashMap<String, String>();
+		tag.put("name", "getting-started");
+
+		String tagLocation = this.mockMvc
+				.perform(
+						post("/tags").contentType(MediaTypes.HAL_JSON).content(
+								objectMapper.writeValueAsString(tag)))
+				.andExpect(status().isCreated())
+				.andExpect(header().string("Location", notNullValue()))
+				.andReturn().getResponse().getHeader("Location");
+		return tagLocation;
+	}
+
+	private void getTag(String tagLocation) throws Exception {
+		this.mockMvc.perform(get(tagLocation)).andExpect(status().isOk())
+			.andExpect(jsonPath("name", is(notNullValue())))
+			.andExpect(jsonPath("_links.tagged-notes", is(notNullValue())));
+	}
+
+	private String createTaggedNote(String tag) throws Exception {
+		Map<String, Object> note = new HashMap<String, Object>();
+		note.put("title", "Tagged note creation with cURL");
+		note.put("body", "An example of how to create a tagged note using cURL");
+		note.put("tags", Arrays.asList(tag));
+
+		String noteLocation = this.mockMvc
+				.perform(
+						post("/notes").contentType(MediaTypes.HAL_JSON).content(
+								objectMapper.writeValueAsString(note)))
+				.andExpect(status().isCreated())
+				.andExpect(header().string("Location", notNullValue()))
+				.andReturn().getResponse().getHeader("Location");
+		return noteLocation;
+	}
+
+	private void getTags(String noteTagsLocation) throws Exception {
+		this.mockMvc.perform(get(noteTagsLocation))
+			.andExpect(status().isOk())
+			.andExpect(jsonPath("_embedded.tags", hasSize(1)));
+	}
+
+	private void tagExistingNote(String noteLocation, String tagLocation) throws Exception {
+		Map<String, Object> update = new HashMap<String, Object>();
+		update.put("tags", Arrays.asList(tagLocation));
+
+		this.mockMvc.perform(
+				patch(noteLocation).contentType(MediaTypes.HAL_JSON).content(
+						objectMapper.writeValueAsString(update)))
+				.andExpect(status().isNoContent());
+	}
+
+	private String getLink(MvcResult result, String rel)
+			throws UnsupportedEncodingException {
+		return JsonPath.parse(result.getResponse().getContentAsString()).read(
+				"_links." + rel + ".href");
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/test/java/com/example/notes/NullOrNotBlankTests.java b/restful-notes-spring-hateoas/src/test/java/com/example/notes/NullOrNotBlankTests.java
new file mode 100644
index 0000000..0868f51
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/test/java/com/example/notes/NullOrNotBlankTests.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2014-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.notes;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Set;
+
+import org.junit.jupiter.api.Test;
+
+import jakarta.validation.ConstraintViolation;
+import jakarta.validation.Validation;
+import jakarta.validation.Validator;
+
+class NullOrNotBlankTests {
+
+	private final Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
+
+	@Test
+	void nullValue() {
+		Set<ConstraintViolation<Constrained>> violations = validator.validate(new Constrained(null));
+		assertThat(violations).isEmpty();
+	}
+
+	@Test
+	void zeroLengthValue() {
+		Set<ConstraintViolation<Constrained>> violations = validator.validate(new Constrained(""));
+		assertThat(violations).hasSize(2);
+	}
+
+	@Test
+	void blankValue() {
+		Set<ConstraintViolation<Constrained>> violations = validator.validate(new Constrained("   "));
+		assertThat(violations).hasSize(2);
+	}
+
+	@Test
+	void nonBlankValue() {
+		Set<ConstraintViolation<Constrained>> violations = validator.validate(new Constrained("test"));
+		assertThat(violations).isEmpty();
+	}
+
+	static class Constrained {
+
+		@NullOrNotBlank
+		private final String value;
+
+		public Constrained(String value) {
+			this.value = value;
+		}
+
+	}
+
+}
diff --git a/restful-notes-spring-hateoas/src/test/resources/org/springframework/restdocs/constraints/ConstraintDescriptions.properties b/restful-notes-spring-hateoas/src/test/resources/org/springframework/restdocs/constraints/ConstraintDescriptions.properties
new file mode 100644
index 0000000..b37e69b
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/test/resources/org/springframework/restdocs/constraints/ConstraintDescriptions.properties
@@ -0,0 +1 @@
+com.example.notes.NullOrNotBlank.description=Must be null or not blank
diff --git a/restful-notes-spring-hateoas/src/test/resources/org/springframework/restdocs/templates/request-fields.snippet b/restful-notes-spring-hateoas/src/test/resources/org/springframework/restdocs/templates/request-fields.snippet
new file mode 100644
index 0000000..cd1e825
--- /dev/null
+++ b/restful-notes-spring-hateoas/src/test/resources/org/springframework/restdocs/templates/request-fields.snippet
@@ -0,0 +1,11 @@
+|===
+|Path|Type|Description|Constraints
+
+{{#fields}}
+|{{path}}
+|{{type}}
+|{{description}}
+|{{constraints}}
+
+{{/fields}}
+|===
\ No newline at end of file