make it clear that Java 21 is supported (#566)

Update examples and references to Java where older Java versions are used to
highlight the support of Java 21.

Specific provider examples are only updated where they support Java 21.

Fixes #557

README.md

@@ -73,7 +73,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'temurin' # See 'Supported distributions' for available options
-    java-version: '17'
+    java-version: '21'
 - run: java HelloWorldApp.java
 ```
 
@@ -84,13 +84,13 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'zulu' # See 'Supported distributions' for available options
-    java-version: '17'
+    java-version: '21'
 - run: java HelloWorldApp.java
 ```
 
 #### Supported version syntax
 The `java-version` input supports an exact version or a version range using [SemVer](https://semver.org/) notation:
-- major versions: `8`, `11`, `16`, `17`
+- major versions: `8`, `11`, `16`, `17`, `21`
 - more specific versions: `17.0`, `11.0`, `11.0.4`, `8.0.232`, `8.0.282+8`
 - early access (EA) versions: `15-ea`, `15.0.0-ea`, `15.0.0-ea.2`, `15.0.0+2-ea`
 
@@ -135,7 +135,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'temurin'
-    java-version: '17'
+    java-version: '21'
     cache: 'gradle'
     cache-dependency-path: | # optional
       sub-project/*.gradle*
@@ -150,7 +150,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'temurin'
-    java-version: '17'
+    java-version: '21'
     cache: 'maven'
     cache-dependency-path: 'sub-project/pom.xml' # optional
 - name: Build with Maven
@@ -164,7 +164,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'temurin'
-    java-version: '17'
+    java-version: '21'
     cache: 'sbt'
     cache-dependency-path: | # optional
       sub-project/build.sbt
@@ -184,7 +184,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'temurin'
-    java-version: '17'
+    java-version: '21'
     cache: 'gradle'
 - run: ./gradlew build --no-daemon
 ```
@@ -204,7 +204,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'temurin'
-    java-version: '17'
+    java-version: '21'
     check-latest: true
 - run: java HelloWorldApp.java
 ```
@@ -216,7 +216,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        java: [ '8', '11', '17' ]
+        java: [ '8', '11', '17', '21' ]
     name: Java ${{ matrix.Java }} sample
     steps:
       - uses: actions/checkout@v4

docs/advanced-usage.md

@@ -25,13 +25,14 @@ See [action.yml](../action.yml) for more details on task inputs.
 Inputs `java-version` and `distribution` are mandatory and needs to be provided. See [Supported distributions](../README.md#Supported-distributions) for a list of available options.
 
 ### Eclipse Temurin
+
 ```yaml
 steps:
 - uses: actions/checkout@v4
 - uses: actions/setup-java@v4
   with:
     distribution: 'temurin'
-    java-version: '11'
+    java-version: '21'
 - run: java -cp java HelloWorldApp
 ```
 
@@ -49,37 +50,40 @@ steps:
 ```
 
 ### Zulu
+
 ```yaml
 steps:
 - uses: actions/checkout@v4
 - uses: actions/setup-java@v4
   with:
     distribution: 'zulu'
-    java-version: '11'
+    java-version: '21'
     java-package: jdk # optional (jdk, jre, jdk+fx or jre+fx) - defaults to jdk
 - run: java -cp java HelloWorldApp
 ```
 
 ### Liberica
+
 ```yaml
 steps:
 - uses: actions/checkout@v4
 - uses: actions/setup-java@v4
   with:
     distribution: 'liberica'
-    java-version: '11'
+    java-version: '21'
     java-package: jdk # optional (jdk, jre, jdk+fx or jre+fx) - defaults to jdk
 - run: java -cp java HelloWorldApp
 ```
 
 ### Microsoft
+
 ```yaml
 steps:
 - uses: actions/checkout@v4
 - uses: actions/setup-java@v4
   with:
     distribution: 'microsoft'
-    java-version: '11'
+    java-version: '21'
 - run: java -cp java HelloWorldApp
 ```
 
@@ -94,7 +98,7 @@ uses: actions/setup-java@v4
 with:
   token: ${{ secrets.GH_DOTCOM_TOKEN }}
   distribution: 'microsoft'
-  java-version: '11'
+  java-version: '21'
 ```
 
 If the runner is not able to access github.com, any Java versions requested during a workflow run must come from the runner's tool cache. See "[Setting up the tool cache on self-hosted runners without internet access](https://docs.github.com/en/enterprise-server@3.2/admin/github-actions/managing-access-to-actions-from-githubcom/setting-up-the-tool-cache-on-self-hosted-runners-without-internet-access)" for more information.
@@ -108,7 +112,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'corretto'
-    java-version: '11'
+    java-version: '21'
 - run: java -cp java HelloWorldApp
 ```
 
@@ -121,12 +125,13 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: 'oracle'
-    java-version: '17'
+    java-version: '21'
 - run: java -cp java HelloWorldApp
 ```
 
 ### Alibaba Dragonwell
 **NOTE:** Alibaba Dragonwell only provides jdk.
+
 ```yaml
 steps:
 - uses: actions/checkout@v4
@@ -188,7 +193,7 @@ If your use-case requires a custom distribution (in the example, alpine-linux is
       - name: fetch latest temurin JDK
         id: fetch_latest_jdk
         run: |
-          major_version={{ env.JAVA_VERSION }} # Example 8 or 11 or 17
+          major_version={{ env.JAVA_VERSION }} # Example 16 or 21 or 22
           cd $RUNNER_TEMP
           response=$(curl -s "https://api.github.com/repos/adoptium/temurin${major_version}-binaries/releases")
           latest_jdk_download_url=$(echo "$response" | jq -r '.[0].assets[] | select(.name | contains("jdk_x64_alpine-linux") and endswith(".tar.gz")) | .browser_download_url')
@@ -439,7 +444,7 @@ steps:
 - uses: actions/setup-java@v4
   with:
     distribution: '<distribution>'
-    java-version: 15
+    java-version: '15'
 ```
 
 The result is a Toolchain with entries for JDKs 8, 11 and 15. You can even combine this with custom JDKs of arbitrary versions:
@@ -523,7 +528,7 @@ If the `java-version-file` input is specified, the action will try to extract th
 Action is able to recognize all variants of the version description according to [jenv](https://github.com/jenv/jenv). 
 Valid entry options:
 ```
-major versions: 8, 11, 16, 17
+major versions: 8, 11, 16, 17, 21
 more specific versions: 1.8.0.2, 17.0, 11.0, 11.0.4, 8.0.232, 8.0.282+8
 early access (EA) versions: 15-ea, 15.0.0-ea, 15.0.0-ea.2, 15.0.0+2-ea
 versions with specified distribution: openjdk64-11.0.2