Use Java 24 for javac and javadoc.

As usual, Guava continues to be usable from Java 8; this CL changes only the build tools that we use to produce it.

RELNOTES=n/a
PiperOrigin-RevId: 744082109

Author: cpovirk

.github/workflows/ci.yml

@@ -40,13 +40,13 @@ jobs:
       # When we specify multiple JDKs, the final one becomes the default, which is used to execute Maven itself.
       # Our Maven configuration then specifies different JDKs to use for some of the steps:
       # - 11 (sometimes) to *download* to support anyone who runs JDiff or our Gradle integration tests (including our doc snapshots and our Java 11 CI test run) but not to use directly
-      # - 23 for running Javadoc and javac (to help people who build Guava locally and might not use a recent JDK to run Maven)
+      # - 24 for running Javadoc and javac (to help people who build Guava locally and might not use a recent JDK to run Maven)
       - name: 'Set up JDKs'
         uses: actions/setup-java@3a4f6e1af504cf6a31855fa899c6aa5355ba6c12 # v4.7.0
         with:
           java-version: |
             ${{ matrix.java }}
-            23
+            24
           distribution: 'temurin'
           cache: 'maven'
       - name: 'Install'
@@ -78,7 +78,7 @@ jobs:
         with:
           # For discussion, see the first setup-java block.
           # The publish-snapshot workflow doesn't run tests, so we don't have to care which version Maven would select for that step.
-          java-version: 23
+          java-version: 24
           distribution: 'temurin'
           server-id: sonatype-nexus-snapshots
           server-username: CI_DEPLOY_USERNAME
@@ -108,7 +108,7 @@ jobs:
           # But we need Java 11 for JDiff.
           java-version: |
             11
-            23
+            24
           distribution: 'temurin'
           cache: 'maven'
       - name: 'Generate latest docs'

android/pom.xml

@@ -342,7 +342,7 @@
           <configuration>
             <toolchains>
               <jdk>
-                <version>23</version>
+                <version>24</version>
               </jdk>
             </toolchains>
           </configuration>
@@ -413,14 +413,14 @@
             (But don't run that if you have put something into ~/.m2/toolchains.xml yourself.)
             -->
             <execution>
-              <id>download-23-and-surefire-version</id>
+              <id>download-24-and-surefire-version</id>
               <goals>
                 <goal>toolchain</goal>
               </goals>
               <configuration>
                 <toolchains>
                   <jdk>
-                    <version>23</version>
+                    <version>24</version>
                     <vendor>temurin</vendor>
                   </jdk>
                   <testJdk>

pom.xml

@@ -343,7 +343,7 @@
           <configuration>
             <toolchains>
               <jdk>
-                <version>23</version>
+                <version>24</version>
               </jdk>
             </toolchains>
           </configuration>
@@ -408,14 +408,14 @@
             (But don't run that if you have put something into ~/.m2/toolchains.xml yourself.)
             -->
             <execution>
-              <id>download-23-and-surefire-version</id>
+              <id>download-24-and-surefire-version</id>
               <goals>
                 <goal>toolchain</goal>
               </goals>
               <configuration>
                 <toolchains>
                   <jdk>
-                    <version>23</version>
+                    <version>24</version>
                     <vendor>temurin</vendor>
                   </jdk>
                   <testJdk>