diff --git a/java/Glacier2/callback/.gitignore b/java/Glacier2/callback/.gitignore
new file mode 100644
index 0000000000..694c577cdd
--- /dev/null
+++ b/java/Glacier2/callback/.gitignore
@@ -0,0 +1,4 @@
+# Gradle generated build files
+bin
+build
+.gradle
diff --git a/java/Glacier2/callback/README.md b/java/Glacier2/callback/README.md
new file mode 100644
index 0000000000..cb818043fa
--- /dev/null
+++ b/java/Glacier2/callback/README.md
@@ -0,0 +1,57 @@
+# Glacier2 Callback
+
+This demo shows how to write a client that establishes a session with a Glacier2 router. It also shows how to implement
+callbacks in this client.
+
+This demo is similar to the [Ice Callback][1] demo, except all communications go through the Glacier router.
+
+The connection between the client and the Glacier2 router is a "bidir" connection, like in the [Ice Bidir][2] demo:
+
+```mermaid
+flowchart LR
+ c[Client
hosts AlarmClock] --bidir connection--> g[Glacier2 router:4063]
+ g --connection1--> s[Server:4061
hosts WakeUpService] --connection2--> g
+```
+
+## Ice prerequisites
+
+- Install Glacier2. See [Ice service installation].
+
+## Building the demo
+
+The demo has two Gradle projects, **client** and **server**, both using the [application plugin].
+
+To build the demo, run:
+
+```shell
+./gradlew build
+```
+
+## Running the demo
+
+Start the Server program in its own terminal:
+
+```shell
+./gradlew :server:run --quiet
+```
+
+Next, start the Glacier2 router in its own terminal:
+
+```shell
+glacier2router --Ice.Config=config.glacier2
+```
+
+> [!TIP]
+> You can also start the Glacier2 router before the server. The order does not matter: the server is identical to the
+> server provided in the [Ice Callback][1] demo and does not depend on Glacier2.
+
+Finally, in a separate terminal, start the client application:
+
+```shell
+./gradlew :client:run --quiet
+```
+
+[Application plugin]: https://docs.gradle.org/current/userguide/application_plugin.html
+
+[1]: ../callback
+[2]: ../bidir
diff --git a/java/Glacier2/callback/client/build.gradle.kts b/java/Glacier2/callback/client/build.gradle.kts
new file mode 100644
index 0000000000..2e5e4658e0
--- /dev/null
+++ b/java/Glacier2/callback/client/build.gradle.kts
@@ -0,0 +1,33 @@
+// Copyright (c) ZeroC, Inc.
+
+plugins {
+ // Apply the application plugin to tell gradle this is a runnable Java application.
+ id("application")
+
+ // Apply the Slice-tools plugin to enable Slice compilation.
+ id("com.zeroc.slice-tools") version "3.8.+"
+
+ // Pull in our local 'convention plugin' to enable linting.
+ id("zeroc-linting")
+}
+
+dependencies {
+ // Add Ice and Glacier2 as implementation dependencies.
+ implementation("com.zeroc:ice:3.8.+")
+ implementation("com.zeroc:glacier2:3.8.+")
+ implementation(project(":util"))
+}
+
+sourceSets {
+ main {
+ // Add the AlarmClock.ice file from the parent slice directory to the main source set.
+ slice {
+ srcDirs("../slice")
+ }
+ }
+}
+
+application {
+ // Specify the main entry point for the application.
+ mainClass.set("com.example.glacier2.callback.client.Client")
+}
diff --git a/java/Glacier2/callback/client/src/main/java/com/example/glacier2/callback/client/Client.java b/java/Glacier2/callback/client/src/main/java/com/example/glacier2/callback/client/Client.java
new file mode 100644
index 0000000000..dddfffdb57
--- /dev/null
+++ b/java/Glacier2/callback/client/src/main/java/com/example/glacier2/callback/client/Client.java
@@ -0,0 +1,82 @@
+// Copyright (c) ZeroC, Inc.
+
+package com.example.glacier2.callback.client;
+
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+import java.util.concurrent.ExecutionException;
+
+import com.example.earlyriser.AlarmClockPrx;
+import com.example.earlyriser.WakeUpServicePrx;
+import com.example.util.Time;
+import com.zeroc.Glacier2.CannotCreateSessionException;
+import com.zeroc.Glacier2.PermissionDeniedException;
+import com.zeroc.Glacier2.RouterPrx;
+import com.zeroc.Glacier2.SessionPrx;
+import com.zeroc.Ice.Communicator;
+import com.zeroc.Ice.Identity;
+import com.zeroc.Ice.ObjectAdapter;
+import com.zeroc.Ice.Util;
+
+class Client {
+ public static void main(String[] args) {
+ // Create an Ice communicator. We'll use this communicator to create proxies and manage outgoing connections.
+ try (Communicator communicator = Util.initialize(args)) {
+
+ // Create a proxy to the Glacier2 router. The addressing information (transport, host and port number) is
+ // derived from the value of Glacier2.Client.Endpoints in the glacier2 router configuration file.
+ RouterPrx router = RouterPrx.createProxy(communicator, "Glacier2/router:tcp -h localhost -p 4063");
+
+ // Create a session with the Glacier2 router. In this demo, the Glacier2 router is configured to accept any
+ // username/password combination. This call establishes a network connection to the Glacier2 router; the
+ // lifetime of the session is the same as the lifetime of the connection.
+ SessionPrx session;
+ try {
+ session = router.createSession(System.getProperty("user.name"), "password");
+ } catch (PermissionDeniedException | CannotCreateSessionException e) {
+ System.out.println("Could not create session: " + e.getMessage());
+ return;
+ }
+
+ // The proxy returned by createSession is null because we did not configure a SessionManager on the Glacier2
+ // router.
+ assert session == null;
+
+ // Obtain a category string from the router. We need to use this category for the identity of
+ // server->client callbacks invoked through the Glacier2 router.
+ String clientCategory = router.getCategoryForClient();
+
+ // Create an object adapter with no name and no configuration, but with our router proxy. This object
+ // adapter is a "bidirectional" object adapter, like the one created by the Ice/Bidir client application.
+ // It does not listen on any port and it does not need to be activated.
+ ObjectAdapter adapter = communicator.createObjectAdapterWithRouter("", router);
+
+ // Register the MockAlarmClock servant with the adapter. It uses the category retrieved from the router.
+ // You can verify the Ring callback is never delivered if you provide a different category.
+ var mockAlarmClock = new MockAlarmClock();
+ AlarmClockPrx alarmClock = AlarmClockPrx.uncheckedCast(
+ adapter.add(mockAlarmClock, new Identity("alarmClock", clientCategory)));
+
+ // Create a proxy to the wake-up service behind the Glacier2 router. Typically, the client cannot connect
+ // directly to this server because it's on an unreachable network.
+ WakeUpServicePrx wakeUpService = WakeUpServicePrx.createProxy(
+ communicator,
+ "wakeUpService:tcp -h localhost -p 4061");
+
+ // Configure the proxy to route requests using the Glacier2 router.
+ wakeUpService = WakeUpServicePrx.uncheckedCast(wakeUpService.ice_router(router));
+
+ // Schedule a wake-up call in 5 seconds. This call establishes the connection to the server; incoming
+ // requests over this connection are handled by the communicator's default object adapter.
+ wakeUpService.wakeMeUp(alarmClock, Time.toTimeStamp(ZonedDateTime.now(ZoneOffset.UTC).plusSeconds(5)));
+ System.out.println("Wake-up call scheduled, falling asleep...");
+ try {
+ // Wait until the user presses the stop button on the alarm clock.
+ mockAlarmClock.stopPressed().get();
+ System.out.println("Stop button pressed, exiting...");
+ } catch (InterruptedException | ExecutionException ex) {
+ System.err.println(ex);
+ }
+ }
+ }
+}
diff --git a/java/Glacier2/callback/client/src/main/java/com/example/glacier2/callback/client/MockAlarmClock.java b/java/Glacier2/callback/client/src/main/java/com/example/glacier2/callback/client/MockAlarmClock.java
new file mode 100644
index 0000000000..4cde495320
--- /dev/null
+++ b/java/Glacier2/callback/client/src/main/java/com/example/glacier2/callback/client/MockAlarmClock.java
@@ -0,0 +1,41 @@
+// Copyright (c) ZeroC, Inc.
+
+package com.example.glacier2.callback.client;
+
+import java.util.concurrent.CompletableFuture;
+
+import com.example.earlyriser.AlarmClock;
+import com.example.earlyriser.ButtonPressed;
+import com.zeroc.Ice.Current;
+
+/**
+ * MockAlarmClock is an Ice servant that implements Slice interface AlarmClock.
+ */
+class MockAlarmClock implements AlarmClock {
+ private boolean _needMoreTime = true;
+
+ private final CompletableFuture _stopPressed;
+
+ public MockAlarmClock() {
+ _stopPressed = new CompletableFuture<>();
+ }
+
+ public CompletableFuture stopPressed() {
+ return _stopPressed;
+ }
+
+ // Implements the method ring from the AlarmClock interface generated by the Slice compiler.
+ @Override
+ public ButtonPressed ring(String message, Current current) {
+ System.out.println("Dispatching ring request { message = '" + message + "' }");
+ if (_needMoreTime) {
+ System.out.println("Returning " + ButtonPressed.Snooze + " to request more time.");
+ _needMoreTime = false; // we only snooze one time
+ return ButtonPressed.Snooze;
+ } else {
+ _stopPressed.complete(null);
+ System.out.println("Returning " + ButtonPressed.Stop + " to stop the alarm.");
+ return ButtonPressed.Stop;
+ }
+ }
+}
diff --git a/java/Glacier2/callback/config.glacier2 b/java/Glacier2/callback/config.glacier2
new file mode 100644
index 0000000000..e75fbc346b
--- /dev/null
+++ b/java/Glacier2/callback/config.glacier2
@@ -0,0 +1,18 @@
+# Config file for glacier2router
+
+# The client-visible endpoint of the Glacier2 router.
+Glacier2.Client.Endpoints=tcp -p 4063
+
+# The server-visible endpoint of the Glacier2 router.
+# You need to configure this endpoint only when your servers make callbacks (call objects implemented by the clients).
+# If you don't use callbacks, don't set this property.
+Glacier2.Server.Endpoints=tcp -h 127.0.0.1
+
+# This Glacier router accepts any username/password combination.
+Glacier2.PermissionsVerifier=Glacier2/NullPermissionsVerifier
+
+# Turn on tracing.
+Glacier2.Client.Trace.Request=1
+Glacier2.Server.Trace.Request=1
+Glacier2.Trace.Session=1
+Glacier2.Trace.RoutingTable=1
diff --git a/java/Glacier2/callback/gradle/wrapper/gradle-wrapper.jar b/java/Glacier2/callback/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000000..a4b76b9530
Binary files /dev/null and b/java/Glacier2/callback/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/java/Glacier2/callback/gradle/wrapper/gradle-wrapper.properties b/java/Glacier2/callback/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000000..d9fbee2e1d
--- /dev/null
+++ b/java/Glacier2/callback/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12.1-all.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/java/Glacier2/callback/gradlew b/java/Glacier2/callback/gradlew
new file mode 100755
index 0000000000..f3b75f3b0d
--- /dev/null
+++ b/java/Glacier2/callback/gradlew
@@ -0,0 +1,251 @@
+#!/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.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+# 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 -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || 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/java/Glacier2/callback/gradlew.bat b/java/Glacier2/callback/gradlew.bat
new file mode 100644
index 0000000000..9d21a21834
--- /dev/null
+++ b/java/Glacier2/callback/gradlew.bat
@@ -0,0 +1,94 @@
+@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
+@rem SPDX-License-Identifier: Apache-2.0
+@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/java/Glacier2/callback/server/build.gradle.kts b/java/Glacier2/callback/server/build.gradle.kts
new file mode 100644
index 0000000000..f46bfec21d
--- /dev/null
+++ b/java/Glacier2/callback/server/build.gradle.kts
@@ -0,0 +1,33 @@
+// Copyright (c) ZeroC, Inc.
+
+plugins {
+ // Apply the application plugin to tell gradle this is a runnable Java application.
+ id("application")
+
+ // Apply the Slice-tools plugin to enable Slice compilation.
+ id("com.zeroc.slice-tools") version "3.8.+"
+
+ // Pull in our local 'convention plugin' to enable linting.
+ id("zeroc-linting")
+}
+
+dependencies {
+ // Add Ice and Glacier2 as implementation dependencies.
+ implementation("com.zeroc:ice:3.8.+")
+ implementation("com.zeroc:glacier2:3.8.+")
+ implementation(project(":util"))
+}
+
+sourceSets {
+ main {
+ // Add the AlarmClock.ice file from the parent slice directory to the main source set.
+ slice {
+ srcDirs("../slice")
+ }
+ }
+}
+
+application {
+ // Specify the main entry point for the application.
+ mainClass.set("com.example.glacier2.callback.server.Server")
+}
diff --git a/java/Glacier2/callback/server/src/main/java/com/example/glacier2/callback/server/Server.java b/java/Glacier2/callback/server/src/main/java/com/example/glacier2/callback/server/Server.java
new file mode 100644
index 0000000000..4679ec1866
--- /dev/null
+++ b/java/Glacier2/callback/server/src/main/java/com/example/glacier2/callback/server/Server.java
@@ -0,0 +1,48 @@
+// Copyright (c) ZeroC, Inc.
+
+package com.example.glacier2.callback.server;
+
+import com.zeroc.Ice.Communicator;
+import com.zeroc.Ice.Identity;
+import com.zeroc.Ice.ObjectAdapter;
+import com.zeroc.Ice.Util;
+
+class Server {
+ public static void main(String[] args) {
+ // Create an Ice communicator. We'll use this communicator to create an object adapter.
+ try (Communicator communicator = Util.initialize(args)) {
+
+ // Create an object adapter that listens for incoming requests and dispatches them to servants.
+ ObjectAdapter adapter = communicator.createObjectAdapterWithEndpoints("WakeUpAdapter", "tcp -p 4061");
+
+ // Register the SimpleWakeUpService servant with the adapter.
+ adapter.add(new SimpleWakeUpService(), new Identity("wakeUpService", ""));
+
+ // Start dispatching requests.
+ adapter.activate();
+ System.out.println("Listening on port 4061...");
+
+ // Register a shutdown hook that calls communicator.shutdown() when the user shuts down the server with
+ // Ctrl+C or similar. The shutdown hook thread also waits until the main thread completes its cleanup.
+ shutdownCommunicatorOnCtrlC(communicator, Thread.currentThread());
+
+ // Wait until the communicator is shut down. Here, this occurs when the user presses Ctrl+C.
+ communicator.waitForShutdown();
+ }
+ }
+
+ private static void shutdownCommunicatorOnCtrlC(Communicator communicator, Thread mainThread) {
+ Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+ System.out.println("Caught Ctrl+C, shutting down...");
+ communicator.shutdown();
+
+ // Wait until the main thread completes.
+ try {
+ mainThread.join();
+ } catch (InterruptedException e) {
+ // No code interrupts the shutdown hook thread in this program.
+ assert false;
+ }
+ }));
+ }
+}
diff --git a/java/Glacier2/callback/server/src/main/java/com/example/glacier2/callback/server/SimpleWakeUpService.java b/java/Glacier2/callback/server/src/main/java/com/example/glacier2/callback/server/SimpleWakeUpService.java
new file mode 100644
index 0000000000..bf61540794
--- /dev/null
+++ b/java/Glacier2/callback/server/src/main/java/com/example/glacier2/callback/server/SimpleWakeUpService.java
@@ -0,0 +1,50 @@
+// Copyright (c) ZeroC, Inc.
+
+package com.example.glacier2.callback.server;
+
+import java.time.Duration;
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+import java.util.concurrent.CompletableFuture;
+
+import com.example.earlyriser.AlarmClockPrx;
+import com.example.earlyriser.ButtonPressed;
+import com.example.earlyriser.WakeUpService;
+import com.example.util.Time;
+import com.zeroc.Ice.Current;
+
+/**
+ * SimpleWakeUpService is an Ice servant that implements Slice interface WakeUpService.
+ */
+class SimpleWakeUpService implements WakeUpService {
+ // Implements the method wakeMeUp from the WakeUpService interface generated by the Slice compiler.
+ @Override
+ public void wakeMeUp(AlarmClockPrx alarmClock, long timeStamp, Current current) {
+ ZonedDateTime timeStampDateTime = Time.toZonedDateTime(timeStamp);
+
+ System.out.println("Dispatching wakeMeUp request { timeStamp = '" + timeStampDateTime.toLocalTime() + "' }");
+
+ // Start a background task to ring the alarm clock.
+ CompletableFuture.runAsync(() -> {
+ try {
+ // Wait until the specified time.
+ var now = ZonedDateTime.now(ZoneOffset.UTC);
+ if (now.isBefore(timeStampDateTime)) {
+ Thread.sleep(Duration.between(now, timeStampDateTime).toMillis());
+ }
+
+ // First ring. This invocation reuses the connection established by the client.
+ ButtonPressed buttonPressed = alarmClock.ring("It's time to wake up!");
+
+ // Keep ringing every 10 seconds until the user presses the stop button.
+ while (buttonPressed == ButtonPressed.Snooze) {
+ Thread.sleep(10_000);
+ buttonPressed = alarmClock.ring("No more snoozing!");
+ }
+ System.out.println("Client pressed Stop on alarm clock.");
+ } catch (InterruptedException ex) {
+ System.err.println(ex);
+ }
+ });
+ }
+}
diff --git a/java/Glacier2/callback/settings.gradle.kts b/java/Glacier2/callback/settings.gradle.kts
new file mode 100644
index 0000000000..cc0c6c4d5b
--- /dev/null
+++ b/java/Glacier2/callback/settings.gradle.kts
@@ -0,0 +1,38 @@
+// Copyright (c) ZeroC, Inc.
+
+pluginManagement {
+ repositories {
+ mavenLocal()
+ gradlePluginPortal()
+ // This demo uses the nightly build of the Slice Tools plugin, published to the ZeroC Maven Nightly repository.
+ maven {
+ url = uri("https://download.zeroc.com/nexus/repository/maven-nightly/")
+ content {
+ includeGroupByRegex("com\\.zeroc.*")
+ }
+ }
+ }
+}
+
+dependencyResolutionManagement {
+ repositories {
+ mavenCentral()
+ // This demo uses the nightly build of Ice, published to the ZeroC Maven Nightly repository.
+ maven {
+ url = uri("https://download.zeroc.com/nexus/repository/maven-nightly/")
+ content {
+ includeGroupByRegex("com\\.zeroc.*")
+ }
+ }
+ }
+}
+
+rootProject.name = "callback"
+
+include("util")
+project(":util").projectDir = file("../../util")
+
+include("client")
+include("server")
+
+includeBuild("../../build-logic")
diff --git a/java/Glacier2/callback/slice/AlarmClock.ice b/java/Glacier2/callback/slice/AlarmClock.ice
new file mode 100644
index 0000000000..57f6a6da16
--- /dev/null
+++ b/java/Glacier2/callback/slice/AlarmClock.ice
@@ -0,0 +1,27 @@
+// Copyright (c) ZeroC, Inc.
+
+["java:identifier:com.example.earlyriser"]
+module EarlyRiser
+{
+ /// Indicates the button pressed when the alarm rang.
+ enum ButtonPressed { Snooze, Stop }
+
+ /// Represents a simple alarm clock. It's the "callback" in this demo, and it's implemented by the client.
+ interface AlarmClock
+ {
+ /// Rings the alarm clock.
+ /// @param message The message to display.
+ /// @return The button pressed by the user.
+ ButtonPressed ring(string message);
+ }
+
+ /// Represents the wake up service provided by the server.
+ interface WakeUpService
+ {
+ /// Schedules a call to {@link AlarmClock::ring} at the specified time.
+ /// @param alarmClock A proxy to the alarm clock to ring.
+ /// @param timeStamp The time to ring the alarm clock. It's encoded as the number of ticks (100 nanoseconds)
+ /// since January 1, 0001 00:00:00 UTC in the Gregorian calendar.
+ void wakeMeUp(AlarmClock* alarmClock, long timeStamp);
+ }
+}
diff --git a/java/Glacier2/greeter/README.md b/java/Glacier2/greeter/README.md
index 0c18d947b3..ca7bfb04c2 100644
--- a/java/Glacier2/greeter/README.md
+++ b/java/Glacier2/greeter/README.md
@@ -14,15 +14,17 @@ a connection to the server, because the server is on a separate network.
- Install Glacier2. See [Ice service installation].
-## Building the Project
+## Building the demo
-This project uses Gradle and the [Application plugin]. To build the client and server applications, run:
+The demo has two Gradle projects, **client** and **server**, both using the [application plugin].
+
+To build the demo, run:
```shell
./gradlew build
```
-## Running the Server
+## Running the demo
Start the Server program in its own terminal:
@@ -40,9 +42,7 @@ glacier2router --Ice.Config=config.glacier2
> You can also start the Glacier2 router before the server. The order does not matter: the server is identical to the
> server provided in the [Ice Greeter][1] demo and does not depend on Glacier2.
-## Running the Client
-
-Then, in a separate terminal, start the client application:
+Finally, in a separate terminal, start the client application:
```shell
./gradlew :client:run --quiet
@@ -50,3 +50,4 @@ Then, in a separate terminal, start the client application:
[Application plugin]: https://docs.gradle.org/current/userguide/application_plugin.html
[Ice service installation]: https://github.com/zeroc-ice/ice/blob/main/NIGHTLY.md#ice-services
+[1]: ../../Ice/greeter/
diff --git a/java/IceGrid/greeter/README.md b/java/IceGrid/greeter/README.md
index f483e35666..e71dca93dd 100644
--- a/java/IceGrid/greeter/README.md
+++ b/java/IceGrid/greeter/README.md
@@ -20,9 +20,11 @@ flowchart LR
- Install IceGrid. See [Ice service installation].
-## Building the Project
+## Building the demo
-This project uses Gradle and the [Application plugin]. To build the client and server applications, run:
+The demo has two Gradle projects, **client** and **server**, both using the [application plugin].
+
+To build the demo, run:
```shell
./gradlew installDist