diff --git a/.github/actions/run-gradle/action.yml b/.github/actions/run-gradle/action.yml
index 00ed95801d..b9f8db6d00 100644
--- a/.github/actions/run-gradle/action.yml
+++ b/.github/actions/run-gradle/action.yml
@@ -64,12 +64,18 @@ runs:
       run: |
         echo "JDK_CI=$JAVA_HOME" >> $GITHUB_ENV
         echo "JDK_EA=${{ inputs.early-access == inputs.java }}" >> $GITHUB_ENV
-    - name: Set up JDK 17
+    - name: Read Gradle JDK toolchain version
+      id: read-jdk-version
+      shell: bash
+      run: |
+        toolchainVersion=$(grep -oP '(?<=^toolchainVersion=).*' gradle/gradle-daemon-jvm.properties)
+        echo "toolchainVersion=${toolchainVersion}" >> $GITHUB_ENV
+    - name: Set up JDK ${{ env.toolchainVersion }}
       id: setup-gradle-jdk
       uses: actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9 # v4.2.1
       if: inputs.java != 'GraalVM'
       with:
-        java-version: 17
+        java-version: ${{ env.toolchainVersion }}
         distribution: temurin
     - name: Setup Gradle
       id: setup-gradle
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index a0618b4141..064f3b5b80 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -46,7 +46,7 @@ updates:
         patterns:
           - "*"
   - package-ecosystem: gradle
-    directory: examples/write-behind-rxjava
+    directory: examples/hibernate
     schedule:
       interval: monthly
     groups:
@@ -55,7 +55,7 @@ updates:
         patterns:
           - "*"
   - package-ecosystem: gradle
-    directory: examples/hibernate
+    directory: examples/indexable
     schedule:
       interval: monthly
     groups:
@@ -81,3 +81,12 @@ updates:
         applies-to: version-updates
         patterns:
           - "*"
+  - package-ecosystem: gradle
+    directory: examples/write-behind-rxjava
+    schedule:
+      interval: monthly
+    groups:
+      gradle-dependencies:
+        applies-to: version-updates
+        patterns:
+          - "*"
diff --git a/.github/workflows/examples.yml b/.github/workflows/examples.yml
index f9c630ddc6..2e361beb9c 100644
--- a/.github/workflows/examples.yml
+++ b/.github/workflows/examples.yml
@@ -84,6 +84,9 @@ jobs:
       - name: Hibernate (jcache)
         working-directory: examples/hibernate
         run: ./gradlew build
+      - name: Indexable
+        working-directory: examples/indexable
+        run: ./gradlew build
       - name: Resilience (failsafe)
         working-directory: examples/resilience-failsafe
         run: ./gradlew build
diff --git a/.java-version b/.java-version
deleted file mode 100644
index 03b6389f32..0000000000
--- a/.java-version
+++ /dev/null
@@ -1 +0,0 @@
-17.0
diff --git a/.tool-versions b/.tool-versions
deleted file mode 100644
index 91abe9545c..0000000000
--- a/.tool-versions
+++ /dev/null
@@ -1 +0,0 @@
-java 17
diff --git a/examples/coalescing-bulkloader-reactor/build.gradle.kts b/examples/coalescing-bulkloader-reactor/build.gradle.kts
index a816509fc0..3430c9c8d6 100644
--- a/examples/coalescing-bulkloader-reactor/build.gradle.kts
+++ b/examples/coalescing-bulkloader-reactor/build.gradle.kts
@@ -17,11 +17,4 @@ testing.suites {
   }
 }
 
-java.toolchain.languageVersion = JavaLanguageVersion.of(
-  System.getenv("JAVA_VERSION")?.toIntOrNull() ?: 17)
-
-tasks.withType<JavaCompile>().configureEach {
-  javaCompiler = javaToolchains.compilerFor {
-    languageVersion = java.toolchain.languageVersion
-  }
-}
+java.toolchain.languageVersion = JavaLanguageVersion.of(21)
diff --git a/examples/coalescing-bulkloader-reactor/gradle/gradle-daemon-jvm.properties b/examples/coalescing-bulkloader-reactor/gradle/gradle-daemon-jvm.properties
index 858feb7e38..63e5bbdf48 100644
--- a/examples/coalescing-bulkloader-reactor/gradle/gradle-daemon-jvm.properties
+++ b/examples/coalescing-bulkloader-reactor/gradle/gradle-daemon-jvm.properties
@@ -1,2 +1,2 @@
 #This file is generated by updateDaemonJvm
-toolchainVersion=17
+toolchainVersion=21
diff --git a/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml b/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml
index 850f3750e9..cb45473fce 100644
--- a/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml
+++ b/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml
@@ -1,7 +1,7 @@
 [versions]
 caffeine = "3.1.8"
 junit = "5.11.0-M2"
-reactor = "3.6.6"
+reactor = "3.6.7"
 truth = "1.4.2"
 versions = "0.51.0"
 
diff --git a/examples/hibernate/build.gradle.kts b/examples/hibernate/build.gradle.kts
index 7708b7a02f..85b2448d36 100644
--- a/examples/hibernate/build.gradle.kts
+++ b/examples/hibernate/build.gradle.kts
@@ -25,15 +25,6 @@ testing.suites {
   }
 }
 
-java.toolchain.languageVersion = JavaLanguageVersion.of(
-  System.getenv("JAVA_VERSION")?.toIntOrNull() ?: 17)
-
-tasks.withType<JavaCompile>().configureEach {
-  javaCompiler = javaToolchains.compilerFor {
-    languageVersion = java.toolchain.languageVersion
-  }
-}
-
 eclipse.classpath.file.beforeMerged {
   if (this is Classpath) {
     val absolutePath = layout.buildDirectory.dir("generated/sources/annotationProcessor/java/main")
diff --git a/examples/hibernate/gradle/gradle-daemon-jvm.properties b/examples/hibernate/gradle/gradle-daemon-jvm.properties
index 858feb7e38..63e5bbdf48 100644
--- a/examples/hibernate/gradle/gradle-daemon-jvm.properties
+++ b/examples/hibernate/gradle/gradle-daemon-jvm.properties
@@ -1,2 +1,2 @@
 #This file is generated by updateDaemonJvm
-toolchainVersion=17
+toolchainVersion=21
diff --git a/examples/indexable/README.md b/examples/indexable/README.md
new file mode 100644
index 0000000000..f5815d2f21
--- /dev/null
+++ b/examples/indexable/README.md
@@ -0,0 +1,82 @@
+In some scenarios, it can be useful to associate a single cache value with alternative keys. Similar
+to a relational database, the cache acts as a table with a primary key, where the value is a row of
+data, and unique hash indexes allow for fast retrieval using secondary keys. When the value is
+updated or deleted, either explicitly or by eviction, the changes should be reflected in the key
+associations. An _Indexable Cache_ provides a straightforward solution for achieving multiple unique
+key lookups to a single value.
+
+### A simple example
+In the schema below, the application needs to find a user by the row id for direct queries, by the
+username during login, and by the email during a password recovery flow.
+
+```sql
+CREATE TABLE user_info (
+  id            bigserial primary key,
+  first_name    varchar(255) NOT NULL,
+  last_name     varchar(255) NOT NULL,
+  email         varchar(255) NOT NULL,
+  username      varchar(255) NOT NULL,
+  password_hash varchar(255) NOT NULL,
+  created_on    timestamp with time zone DEFAULT CURRENT_TIMESTAMP,
+  modified_on   timestamp with time zone DEFAULT CURRENT_TIMESTAMP,
+);
+CREATE UNIQUE INDEX user_info_email_idx ON user_info (email);
+CREATE UNIQUE INDEX user_info_username_idx ON user_info (username);
+```
+
+Java's [Data-Oriented Programming][] approach represents each lookup key as a distinct type and uses
+pattern matching when loading an entry on a cache miss.
+
+```java
+sealed interface UserKey permits UserById, UserByLogin, UserByEmail {
+  record UserByLogin(String login) implements UserKey {}
+  record UserByEmail(String email) implements UserKey {}
+  record UserById(long id) implements UserKey {}
+}
+
+private User findUser(UserKey key) {
+  Condition condition = switch (key) {
+    case UserById(var id) -> USER_INFO.ID.eq(id);
+    case UserByLogin(var login) -> USER_INFO.USERNAME.eq(login);
+    case UserByEmail(var email) -> USER_INFO.EMAIL.eq(email.toLowerCase());
+  };
+  return db.selectFrom(USER_INFO).where(condition).fetchOneInto(User.class);
+}
+```
+
+The cache is constructed with functions to build the indexes, the data loader, and the bounding
+constraints. The value can then be queried using the typed key.
+
+```java
+var cache = new IndexedCache.Builder<UserKey, User>()
+    .primaryKey(user -> new UserById(user.id()))
+    .addSecondaryKey(user -> new UserByLogin(user.login()))
+    .addSecondaryKey(user -> new UserByEmail(user.email()))
+    .expireAfterWrite(Duration.ofMinutes(5))
+    .maximumSize(10_000)
+    .build(this::findUser);
+
+var userByEmail = cache.get(new UserByEmail("john.doe@example.com"));
+var userByLogin = cache.get(new UserByLogin("john.doe"));
+assertThat(userByEmail).isSameInstanceAs(userByLogin);
+```
+
+### How it works
+The sample [IndexedCache][] combines a key-value cache with an associated mapping from the
+individual keys to the entry's complete set. Consistency is maintained by acquiring the write lock
+through the cache using the primary key before updating the index. This prevents race conditions
+when the entry is concurrently updated and evicted, which could otherwise lead to missing or
+non-resident key associations in the index. On eviction, a listener discards the keys while holding
+the cache's entry lock.
+
+When a value is not found and must be loaded, an important performance optimization is to avoid a
+cache stampede of redundant queries by performing that work once for all callers. This is
+challenging when there are alternative lookup keys, as the cache is unaware of a canonical key to
+lock against until the value is loaded. While using a single shared lock across all keys could solve
+this, it would also penalize distinct entries by the slow loading time of preceding calls. A
+[StripedLock][] provides a balanced solution by memoizing per key and using a last-write-wins policy
+if the same value is loaded by concurrent calls using different keys.
+
+[Data-Oriented Programming]: https://inside.java/2024/05/23/dop-v1-1-introduction
+[IndexedCache]: src/main/java/com/github/benmanes/caffeine/examples/indexable/IndexedCache.java
+[StripedLock]: https://guava.dev/releases/snapshot-jre/api/docs/com/google/common/util/concurrent/Striped.html
diff --git a/examples/indexable/build.gradle.kts b/examples/indexable/build.gradle.kts
new file mode 100644
index 0000000000..4e67b3e05a
--- /dev/null
+++ b/examples/indexable/build.gradle.kts
@@ -0,0 +1,21 @@
+plugins {
+  `java-library`
+  alias(libs.plugins.versions)
+}
+
+dependencies {
+  implementation(libs.caffeine)
+  implementation(libs.guava)
+
+  testImplementation(libs.junit.jupiter)
+  testImplementation(libs.guava.testlib)
+  testImplementation(libs.truth)
+}
+
+java.toolchain.languageVersion = JavaLanguageVersion.of(21)
+
+testing.suites {
+  val test by getting(JvmTestSuite::class) {
+    useJUnitJupiter()
+  }
+}
diff --git a/examples/indexable/gradle/gradle-daemon-jvm.properties b/examples/indexable/gradle/gradle-daemon-jvm.properties
new file mode 100644
index 0000000000..63e5bbdf48
--- /dev/null
+++ b/examples/indexable/gradle/gradle-daemon-jvm.properties
@@ -0,0 +1,2 @@
+#This file is generated by updateDaemonJvm
+toolchainVersion=21
diff --git a/examples/indexable/gradle/libs.versions.toml b/examples/indexable/gradle/libs.versions.toml
new file mode 100644
index 0000000000..dac0a28fac
--- /dev/null
+++ b/examples/indexable/gradle/libs.versions.toml
@@ -0,0 +1,16 @@
+[versions]
+caffeine = "3.1.8"
+guava = "33.2.1-jre"
+junit-jupiter = "5.11.0-M2"
+truth = "1.4.2"
+versions = "0.51.0"
+
+[libraries]
+caffeine = { module = "com.github.ben-manes.caffeine:caffeine", version.ref = "caffeine" }
+guava = { module = "com.google.guava:guava", version.ref = "guava" }
+guava-testlib = { module = "com.google.guava:guava-testlib", version.ref = "guava" }
+junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-jupiter" }
+truth = { module = "com.google.truth:truth", version.ref = "truth" }
+
+[plugins]
+versions = { id = "com.github.ben-manes.versions", version.ref = "versions" }
diff --git a/examples/indexable/gradle/wrapper/gradle-wrapper.jar b/examples/indexable/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000000..e6441136f3
Binary files /dev/null and b/examples/indexable/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/examples/indexable/gradle/wrapper/gradle-wrapper.properties b/examples/indexable/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000000..c9e6332d32
--- /dev/null
+++ b/examples/indexable/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,7 @@
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+validateDistributionUrl=true
+zipStorePath=wrapper/dists
+networkTimeout=10000
diff --git a/examples/indexable/gradlew b/examples/indexable/gradlew
new file mode 100755
index 0000000000..b740cf1339
--- /dev/null
+++ b/examples/indexable/gradlew
@@ -0,0 +1,249 @@
+#!/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/HEAD/platforms/jvm/plugins-application/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
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&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: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$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
+
+
+# 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"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$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/examples/indexable/gradlew.bat b/examples/indexable/gradlew.bat
new file mode 100644
index 0000000000..25da30dbde
--- /dev/null
+++ b/examples/indexable/gradlew.bat
@@ -0,0 +1,92 @@
+@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=.
+@rem This is normally unused
+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% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+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% equ 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!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/examples/indexable/settings.gradle.kts b/examples/indexable/settings.gradle.kts
new file mode 100644
index 0000000000..50df97547a
--- /dev/null
+++ b/examples/indexable/settings.gradle.kts
@@ -0,0 +1,15 @@
+plugins {
+  id("com.gradle.develocity") version "3.17.4"
+  id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.1"
+  id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
+}
+
+dependencyResolutionManagement {
+  repositories {
+    mavenCentral()
+  }
+}
+
+apply(from = "../../gradle/develocity.gradle")
+
+rootProject.name = "indexable"
diff --git a/examples/indexable/src/main/java/com/github/benmanes/caffeine/examples/indexable/IndexedCache.java b/examples/indexable/src/main/java/com/github/benmanes/caffeine/examples/indexable/IndexedCache.java
new file mode 100644
index 0000000000..0494f8d238
--- /dev/null
+++ b/examples/indexable/src/main/java/com/github/benmanes/caffeine/examples/indexable/IndexedCache.java
@@ -0,0 +1,180 @@
+/*
+ * Copyright 2024 Ben Manes. All Rights Reserved.
+ *
+ * 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
+ *
+ *     http://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.github.benmanes.caffeine.examples.indexable;
+
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static java.util.Objects.requireNonNull;
+
+import java.time.Duration;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.locks.Lock;
+import java.util.function.Function;
+
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import com.github.benmanes.caffeine.cache.Ticker;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+import com.google.common.util.concurrent.Striped;
+
+/**
+ * A cache abstraction that allows the entry to looked up by alternative keys. This approach mirrors
+ * a database table where a row is stored by its primary key, it contains all of the columns that
+ * identify it, and the unique indexes are additional mappings defined by the column mappings. This
+ * class similarly stores the in the value once in the cache by its primary key and maintains a
+ * secondary mapping for lookups by using indexing functions to derive the keys.
+ *
+ * @author ben.manes@gmail.com (Ben Manes)
+ */
+public final class IndexedCache<K, V> {
+  final ConcurrentMap<K, Index<K>> indexes;
+  final Function<K, V> mappingFunction;
+  final Function<V, Index<K>> indexer;
+  final Striped<Lock> locks;
+  final Cache<K, V> store;
+
+  private IndexedCache(Caffeine<Object, Object> cacheBuilder, Function<K, V> mappingFunction,
+      Function<V, K> primary, Set<Function<V, K>> secondaries) {
+    this.locks = Striped.lock(1_000);
+    this.mappingFunction = mappingFunction;
+    this.indexes = new ConcurrentHashMap<>();
+    this.store = cacheBuilder
+        .evictionListener((key, value, cause) ->
+            indexes.keySet().removeAll(indexes.get(key).allKeys()))
+        .build();
+    this.indexer = value -> new Index<>(primary.apply(value),
+        secondaries.stream().map(indexer -> indexer.apply(value)).collect(toImmutableSet()));
+  }
+
+  /** Returns the value associated with the key or {@code null} if not found. */
+  public V getIfPresent(K key) {
+    var index = indexes.get(key);
+    return (index == null) ? null : store.getIfPresent(index.primaryKey());
+  }
+
+  /**
+   * Returns the value associated with the key, obtaining that value from the
+   * {@code mappingFunction} if necessary. The entire method invocation is performed atomically, so
+   * the function is applied at most once per key. As the value may be looked up by alternative
+   * keys, those function invocations may be executed in parallel and will replace any existing
+   * mappings when completed.
+   */
+  public V get(K key) {
+    var value = getIfPresent(key);
+    if (value != null) {
+      return value;
+    }
+
+    var lock = locks.get(key);
+    lock.lock();
+    try {
+      value = getIfPresent(key);
+      if (value != null) {
+        return value;
+      }
+
+      value = mappingFunction.apply(key);
+      if (value == null) {
+        return null;
+      }
+
+      put(value);
+      return value;
+    } finally {
+      lock.unlock();
+    }
+  }
+
+  /** Associates the {@code value} with its keys, replacing the old value and keys if present. */
+  public V put(V value) {
+    requireNonNull(value);
+    var index = indexer.apply(value);
+    return store.asMap().compute(index.primaryKey(), (key, oldValue) -> {
+      if (oldValue != null) {
+        indexes.keySet().removeAll(Sets.difference(
+            indexes.get(index.primaryKey()).allKeys(), index.allKeys()));
+      }
+      for (var indexKey : index.allKeys()) {
+        indexes.put(indexKey, index);
+      }
+      return value;
+    });
+  }
+
+  /** Discards any cached value and its keys. */
+  public void invalidate(K key) {
+    var index = indexes.get(key);
+    if (index == null) {
+      return;
+    }
+
+    store.asMap().computeIfPresent(index.primaryKey(), (k, v) -> {
+      indexes.keySet().removeAll(index.allKeys());
+      return null;
+    });
+  }
+
+  private record Index<K>(K primaryKey, Set<K> secondaryKeys) {
+    public Set<K> allKeys() {
+      return Sets.union(Set.of(primaryKey), secondaryKeys);
+    }
+  }
+
+  /** This builder could be extended to support most cache options, e.g. excluding for weak keys. */
+  public static final class Builder<K, V> {
+    final Caffeine<Object, Object> cacheBuilder;
+    final ImmutableSet.Builder<Function<V, K>> secondaries;
+
+    Function<V, K> primary;
+
+    public Builder() {
+      cacheBuilder = Caffeine.newBuilder();
+      secondaries = ImmutableSet.builder();
+    }
+
+    /** See {@link Caffeine#expireAfterWrite(Duration)}. */
+    public Builder<K, V> expireAfterWrite(Duration duration) {
+      cacheBuilder.expireAfterWrite(duration);
+      return this;
+    }
+
+    /** See {@link Caffeine#ticker(Duration)}. */
+    public Builder<K, V> ticker(Ticker ticker) {
+      cacheBuilder.ticker(ticker);
+      return this;
+    }
+
+    /** Adds the functions to extract the indexable keys. */
+    public Builder<K, V> primaryKey(Function<V, K> primary) {
+      this.primary = requireNonNull(primary);
+      return this;
+    }
+
+    /** Adds the functions to extract the indexable keys. */
+    public Builder<K, V> addSecondaryKey(Function<V, K> secondary) {
+      secondaries.add(requireNonNull(secondary));
+      return this;
+    }
+
+    public IndexedCache<K, V> build(Function<K, V> mappingFunction) {
+      requireNonNull(primary);
+      requireNonNull(mappingFunction);
+      return new IndexedCache<K, V>(cacheBuilder, mappingFunction, primary, secondaries.build());
+    }
+  }
+}
diff --git a/examples/indexable/src/test/java/com/github/benmanes/caffeine/examples/indexable/IndexedCacheTest.java b/examples/indexable/src/test/java/com/github/benmanes/caffeine/examples/indexable/IndexedCacheTest.java
new file mode 100644
index 0000000000..2a26b3e08a
--- /dev/null
+++ b/examples/indexable/src/test/java/com/github/benmanes/caffeine/examples/indexable/IndexedCacheTest.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2024 Ben Manes. All Rights Reserved.
+ *
+ * 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
+ *
+ *     http://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.github.benmanes.caffeine.examples.indexable;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import java.time.Duration;
+import java.util.Set;
+import java.util.function.Predicate;
+
+import org.junit.jupiter.api.Test;
+
+import com.github.benmanes.caffeine.examples.indexable.IndexedCacheTest.UserKey.UserById;
+import com.github.benmanes.caffeine.examples.indexable.IndexedCacheTest.UserKey.UserByLogin;
+import com.github.benmanes.caffeine.examples.indexable.IndexedCacheTest.UserKey.UserByPhone;
+import com.google.common.testing.FakeTicker;
+
+/**
+ * @author ben.manes@gmail.com (Ben Manes)
+ */
+public final class IndexedCacheTest {
+  private final Set<User> users = Set.of(
+      new User(1, "john.doe", "+1 (555) 555-5555"),
+      new User(2, "jane.doe", "+1 (777) 777-7777"));
+
+  @Test
+  public void basicUsage() {
+    var ticker = new FakeTicker();
+    var cache = new IndexedCache.Builder<UserKey, User>()
+        .addSecondaryKey(user -> new UserByLogin(user.login()))
+        .addSecondaryKey(user -> new UserByPhone(user.phone()))
+        .primaryKey(user -> new UserById(user.id()))
+        .expireAfterWrite(Duration.ofMinutes(1))
+        .ticker(ticker::read)
+        .build(this::findUser);
+
+    var johnById = cache.get(new UserById(1));
+    assertThat(johnById).isNotNull();
+
+    var johnByLogin = cache.get(new UserByLogin("john.doe"));
+    assertThat(johnByLogin).isSameInstanceAs(johnById);
+
+    var janeByLogin = cache.get(new UserByLogin("jane.doe"));
+    assertThat(janeByLogin).isNotSameInstanceAs(johnById);
+
+    assertThat(cache.store.asMap()).hasSize(2);
+    assertThat(cache.indexes).hasSize(6);
+
+    cache.invalidate(new UserByPhone("+1 (555) 555-5555"));
+    assertThat(cache.getIfPresent(new UserByLogin("john.doe"))).isNull();
+
+    assertThat(cache.store.asMap()).hasSize(1);
+    assertThat(cache.indexes).hasSize(3);
+
+    ticker.advance(Duration.ofHours(1));
+    cache.store.cleanUp();
+
+    assertThat(cache.store.asMap()).isEmpty();
+    assertThat(cache.indexes).isEmpty();
+  }
+
+  /** Returns the user found in the system of record. */
+  private User findUser(UserKey key) {
+    Predicate<User> predicate = switch (key) {
+      case UserById(int id) -> user -> user.id() == id;
+      case UserByLogin(var login) -> user -> user.login().equals(login);
+      case UserByPhone(var phone) -> user -> user.phone().equals(phone);
+    };
+    return users.stream().filter(predicate).findAny().orElse(null);
+  }
+
+  sealed interface UserKey permits UserById, UserByLogin, UserByPhone {
+    record UserByLogin(String login) implements UserKey {}
+    record UserByPhone(String phone) implements UserKey {}
+    record UserById(int id) implements UserKey {}
+  }
+  record User(int id, String login, String phone) {}
+}
diff --git a/examples/resilience-failsafe/build.gradle.kts b/examples/resilience-failsafe/build.gradle.kts
index ddf8b54df4..d73d73b2b3 100644
--- a/examples/resilience-failsafe/build.gradle.kts
+++ b/examples/resilience-failsafe/build.gradle.kts
@@ -16,12 +16,3 @@ testing.suites {
     useJUnitJupiter()
   }
 }
-
-java.toolchain.languageVersion = JavaLanguageVersion.of(
-  System.getenv("JAVA_VERSION")?.toIntOrNull() ?: 17)
-
-tasks.withType<JavaCompile>().configureEach {
-  javaCompiler = javaToolchains.compilerFor {
-    languageVersion = java.toolchain.languageVersion
-  }
-}
diff --git a/examples/resilience-failsafe/gradle/gradle-daemon-jvm.properties b/examples/resilience-failsafe/gradle/gradle-daemon-jvm.properties
index 858feb7e38..63e5bbdf48 100644
--- a/examples/resilience-failsafe/gradle/gradle-daemon-jvm.properties
+++ b/examples/resilience-failsafe/gradle/gradle-daemon-jvm.properties
@@ -1,2 +1,2 @@
 #This file is generated by updateDaemonJvm
-toolchainVersion=17
+toolchainVersion=21
diff --git a/examples/resilience-failsafe/settings.gradle.kts b/examples/resilience-failsafe/settings.gradle.kts
index 5fa0e06224..5e04180ef8 100644
--- a/examples/resilience-failsafe/settings.gradle.kts
+++ b/examples/resilience-failsafe/settings.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-  id("com.gradle.develocity") version "3.17.4"
+  id("com.gradle.develocity") version "3.17.5"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.1"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/examples/write-behind-rxjava/build.gradle.kts b/examples/write-behind-rxjava/build.gradle.kts
index facadf7abb..4d63ae2538 100644
--- a/examples/write-behind-rxjava/build.gradle.kts
+++ b/examples/write-behind-rxjava/build.gradle.kts
@@ -16,12 +16,3 @@ testing.suites {
     useJUnitJupiter()
   }
 }
-
-java.toolchain.languageVersion = JavaLanguageVersion.of(
-  System.getenv("JAVA_VERSION")?.toIntOrNull() ?: 17)
-
-tasks.withType<JavaCompile>().configureEach {
-  javaCompiler = javaToolchains.compilerFor {
-    languageVersion = java.toolchain.languageVersion
-  }
-}
diff --git a/examples/write-behind-rxjava/gradle/gradle-daemon-jvm.properties b/examples/write-behind-rxjava/gradle/gradle-daemon-jvm.properties
index 858feb7e38..63e5bbdf48 100644
--- a/examples/write-behind-rxjava/gradle/gradle-daemon-jvm.properties
+++ b/examples/write-behind-rxjava/gradle/gradle-daemon-jvm.properties
@@ -1,2 +1,2 @@
 #This file is generated by updateDaemonJvm
-toolchainVersion=17
+toolchainVersion=21
diff --git a/gradle/gradle-daemon-jvm.properties b/gradle/gradle-daemon-jvm.properties
index 858feb7e38..63e5bbdf48 100644
--- a/gradle/gradle-daemon-jvm.properties
+++ b/gradle/gradle-daemon-jvm.properties
@@ -1,2 +1,2 @@
 #This file is generated by updateDaemonJvm
-toolchainVersion=17
+toolchainVersion=21
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 6d19ace364..44fb3b5b94 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -29,7 +29,7 @@ expiring-map = "0.5.11"
 fast-filter = "1.0.2"
 fastutil = "8.5.13"
 felix-framework = "7.0.5"
-felix-scr = "2.2.10"
+felix-scr = "2.2.12"
 findsecbugs = "1.13.0"
 flip-tables = "1.1.1"
 forbidden-apis = "3.7"
@@ -53,7 +53,7 @@ jcache = "1.1.1"
 jcommander = "1.82"
 jctools = "4.0.5"
 jfreechart = "1.5.4"
-jgit = "6.9.0.202403050737-r"
+jgit = "6.10.0.202406032230-r"
 jmh-core = "1.37"
 jmh-plugin = "0.7.2"
 jmh-report = "0.9.6"
@@ -86,7 +86,7 @@ snakeyaml = "2.2"
 sonarqube = "5.0.0.4638"
 spotbugs-contrib = "7.6.4"
 spotbugs-core = "4.8.5"
-spotbugs-plugin = "6.0.15"
+spotbugs-plugin = "6.0.16"
 stream = "2.9.8"
 tcache = "2.0.1"
 testng = "7.10.2"
diff --git a/gradle/plugins/gradle/gradle-daemon-jvm.properties b/gradle/plugins/gradle/gradle-daemon-jvm.properties
index 858feb7e38..63e5bbdf48 100644
--- a/gradle/plugins/gradle/gradle-daemon-jvm.properties
+++ b/gradle/plugins/gradle/gradle-daemon-jvm.properties
@@ -1,2 +1,2 @@
 #This file is generated by updateDaemonJvm
-toolchainVersion=17
+toolchainVersion=21
diff --git a/jitpack.yml b/jitpack.yml
index f57d7fe8e2..b4da4048f1 100644
--- a/jitpack.yml
+++ b/jitpack.yml
@@ -1,5 +1,5 @@
 before_install:
   - source "$HOME/.sdkman/bin/sdkman-init.sh"
   - sdk update
-  - sdk install java 17.0.10-zulu
-  - sdk use java 17.0.10-zulu
+  - sdk install java 21.0.3-zulu
+  - sdk use java 21.0.3-zulu