java langgraph-checkpoint

langgraph-java/.gitignore

@@ -0,0 +1,90 @@
+##############################
+## Java
+##############################
+.mtj.tmp/
+*.class
+*.jar
+*.war
+*.ear
+*.nar
+hs_err_pid*
+replay_pid*
+
+##############################
+## Maven
+##############################
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+pom.xml.bak
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+.mvn/wrapper/maven-wrapper.jar
+
+##############################
+## Gradle
+##############################
+bin/
+build/
+.gradle
+.gradletasknamecache
+gradle-app.setting
+!gradle-wrapper.jar
+
+##############################
+## IntelliJ
+##############################
+out/
+.idea/
+.idea_modules/
+*.iml
+*.ipr
+*.iws
+
+##############################
+## Eclipse
+##############################
+.settings/
+bin/
+tmp/
+.metadata
+.classpath
+.project
+*.tmp
+*.bak
+*.swp
+*~.nib
+local.properties
+.loadpath
+.factorypath
+
+##############################
+## NetBeans
+##############################
+nbproject/private/
+build/
+nbbuild/
+dist/
+nbdist/
+nbactions.xml
+nb-configuration.xml
+
+##############################
+## Visual Studio Code
+##############################
+.vscode/
+.code-workspace
+
+##############################
+## OS X
+##############################
+.DS_Store
+
+##############################
+## Miscellaneous
+##############################
+*.log

langgraph-java/README.md

@@ -0,0 +1,63 @@
+# LangGraph Java
+
+A Java port of LangGraph, a framework for building stateful, observable applications with large language models (LLMs).
+
+## Project Structure
+
+- `langgraph-checkpoint`: Base persistence interfaces
+- `langgraph-core`: Main library with channels, Pregel, and StateGraph
+- `langgraph-examples`: Example applications
+
+## Requirements
+
+- Java 17 or higher
+- Gradle 7.0 or higher
+
+## Building
+
+```bash
+./gradlew build
+```
+
+## Features
+
+- Graph-based architecture with nodes and edges
+- Type-safe state schema using Java Records
+- Cyclical execution patterns
+- Checkpoint integration for persistence
+- Streaming support
+- Human-in-the-loop capabilities
+
+## Usage Example
+
+```java
+// Create a graph with our schema
+StateGraph<CounterState> graph = new StateGraph<>(CounterState.class);
+
+// Add nodes
+graph.addNode("increment", state -> {
+    Map<String, Object> updates = new HashMap<>();
+    updates.put("count", state.count() + 1);
+    return updates;
+});
+
+// Add edges
+graph.addEdge(START, "increment");
+graph.addEdge("increment", "check");
+
+// Add conditional edge
+graph.addConditionalEdges("check", state -> {
+    if (state.count() >= 3) {
+        return "finish";
+    }
+    return "increment";
+});
+
+// Compile and run
+CompiledStateGraph<CounterState> compiled = graph.compile();
+CounterState result = compiled.invoke(new CounterState(0, ""));
+```
+
+## License
+
+This project is licensed under the MIT License - see the LICENSE file for details.

langgraph-java/build.gradle

@@ -0,0 +1,39 @@
+plugins {
+    id 'java-library'
+}
+
+allprojects {
+    group = 'com.langgraph'
+    version = '0.1.0-SNAPSHOT'
+
+    repositories {
+        mavenCentral()
+    }
+}
+
+subprojects {
+    apply plugin: 'java-library'
+    
+    java {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+    
+    tasks.withType(JavaCompile) {
+        options.encoding = 'UTF-8'
+        options.compilerArgs << '-parameters'
+    }
+    
+    dependencies {
+        // Testing dependencies
+        testImplementation 'org.junit.jupiter:junit-jupiter-api:5.9.2'
+        testImplementation 'org.junit.jupiter:junit-jupiter-params:5.9.2'
+        testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.9.2'
+        testImplementation 'org.mockito:mockito-core:5.2.0'
+        testImplementation 'org.assertj:assertj-core:3.24.2'
+    }
+    
+    test {
+        useJUnitPlatform()
+    }
+}

langgraph-java/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.13-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

langgraph-java/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, 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 "$JAVACMD" "$@"

langgraph-java/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

langgraph-java/langgraph-checkpoint/build.gradle

@@ -0,0 +1,5 @@
+dependencies {
+    // MessagePack for serialization
+    implementation 'org.msgpack:msgpack-core:0.9.3'
+    implementation 'org.msgpack:jackson-dataformat-msgpack:0.9.3'
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/base/AsyncBaseCheckpointSaver.java

@@ -0,0 +1,60 @@
+package com.langgraph.checkpoint.base;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Asynchronous interface for saving and loading checkpoints.
+ */
+public interface AsyncBaseCheckpointSaver {
+    /**
+     * Create a new checkpoint asynchronously.
+     *
+     * @param threadId The ID of the thread to checkpoint
+     * @param channelValues The values of the channels to checkpoint
+     * @return CompletableFuture with the ID of the new checkpoint
+     */
+    CompletableFuture<String> checkpointAsync(String threadId, Map<String, Object> channelValues);
+
+    /**
+     * Get values from a checkpoint asynchronously.
+     *
+     * @param checkpointId The ID of the checkpoint to load
+     * @return CompletableFuture with the channel values from the checkpoint, or empty if not found
+     */
+    CompletableFuture<Optional<Map<String, Object>>> getValuesAsync(String checkpointId);
+
+    /**
+     * List all checkpoints for a thread asynchronously.
+     *
+     * @param threadId The ID of the thread
+     * @return CompletableFuture with list of checkpoint IDs
+     */
+    CompletableFuture<List<String>> listAsync(String threadId);
+
+    /**
+     * Get the latest checkpoint for a thread asynchronously.
+     *
+     * @param threadId The ID of the thread
+     * @return CompletableFuture with the ID of the latest checkpoint, or empty if none exists
+     */
+    CompletableFuture<Optional<String>> latestAsync(String threadId);
+    
+    /**
+     * Delete a checkpoint asynchronously.
+     *
+     * @param checkpointId The ID of the checkpoint to delete
+     * @return CompletableFuture completed when deletion is done
+     */
+    CompletableFuture<Void> deleteAsync(String checkpointId);
+    
+    /**
+     * Clear all checkpoints for a thread asynchronously.
+     *
+     * @param threadId The ID of the thread
+     * @return CompletableFuture completed when clearing is done
+     */
+    CompletableFuture<Void> clearAsync(String threadId);
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/base/BaseCheckpointSaver.java

@@ -0,0 +1,57 @@
+package com.langgraph.checkpoint.base;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+/**
+ * Interface for saving and loading checkpoints.
+ */
+public interface BaseCheckpointSaver {
+    /**
+     * Create a new checkpoint.
+     *
+     * @param threadId The ID of the thread to checkpoint
+     * @param channelValues The values of the channels to checkpoint
+     * @return The ID of the new checkpoint
+     */
+    String checkpoint(String threadId, Map<String, Object> channelValues);
+
+    /**
+     * Get values from a checkpoint.
+     *
+     * @param checkpointId The ID of the checkpoint to load
+     * @return The channel values from the checkpoint, or empty if not found
+     */
+    Optional<Map<String, Object>> getValues(String checkpointId);
+
+    /**
+     * List all checkpoints for a thread.
+     *
+     * @param threadId The ID of the thread
+     * @return List of checkpoint IDs
+     */
+    List<String> list(String threadId);
+
+    /**
+     * Get the latest checkpoint for a thread.
+     *
+     * @param threadId The ID of the thread
+     * @return The ID of the latest checkpoint, or empty if none exists
+     */
+    Optional<String> latest(String threadId);
+    
+    /**
+     * Delete a checkpoint.
+     *
+     * @param checkpointId The ID of the checkpoint to delete
+     */
+    void delete(String checkpointId);
+    
+    /**
+     * Clear all checkpoints for a thread.
+     *
+     * @param threadId The ID of the thread
+     */
+    void clear(String threadId);
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/base/ID.java

@@ -0,0 +1,81 @@
+package com.langgraph.checkpoint.base;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Base64;
+import java.util.UUID;
+
+/**
+ * Utility class for generating deterministic IDs.
+ */
+public final class ID {
+    private ID() {
+        // Prevent instantiation
+    }
+    
+    /**
+     * Generate a deterministic UUID based on a namespace and name.
+     *
+     * @param namespace The namespace for the ID
+     * @param name The name within the namespace
+     * @return A UUID
+     */
+    public static UUID uuid(String namespace, String name) {
+        try {
+            MessageDigest md = MessageDigest.getInstance("SHA-1");
+            md.update(namespace.getBytes(StandardCharsets.UTF_8));
+            md.update(name.getBytes(StandardCharsets.UTF_8));
+            byte[] digest = md.digest();
+            
+            // Set the version (4) and variant (RFC4122) bits
+            digest[6] = (byte) ((digest[6] & 0x0F) | 0x40);
+            digest[8] = (byte) ((digest[8] & 0x3F) | 0x80);
+            
+            long msb = 0;
+            long lsb = 0;
+            
+            for (int i = 0; i < 8; i++) {
+                msb = (msb << 8) | (digest[i] & 0xff);
+            }
+            
+            for (int i = 8; i < 16; i++) {
+                lsb = (lsb << 8) | (digest[i] & 0xff);
+            }
+            
+            return new UUID(msb, lsb);
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException("SHA-1 algorithm not available", e);
+        }
+    }
+    
+    /**
+     * Generate a checkpoint ID.
+     *
+     * @param threadId The thread ID
+     * @return A checkpoint ID
+     */
+    public static String checkpointId(String threadId) {
+        return uuid("checkpoint", threadId + "/" + System.currentTimeMillis()).toString();
+    }
+    
+    /**
+     * Generate a URL-safe base64 encoded ID.
+     *
+     * @param namespace The namespace for the ID
+     * @param name The name within the namespace
+     * @return A URL-safe base64-encoded ID
+     */
+    public static String urlSafeId(String namespace, String name) {
+        try {
+            MessageDigest md = MessageDigest.getInstance("SHA-256");
+            md.update(namespace.getBytes(StandardCharsets.UTF_8));
+            md.update(name.getBytes(StandardCharsets.UTF_8));
+            byte[] digest = md.digest();
+            
+            return Base64.getUrlEncoder().withoutPadding().encodeToString(digest);
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException("SHA-256 algorithm not available", e);
+        }
+    }
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/base/memory/AsyncMemoryCheckpointSaver.java

@@ -0,0 +1,79 @@
+package com.langgraph.checkpoint.base.memory;
+
+import com.langgraph.checkpoint.base.AsyncBaseCheckpointSaver;
+import com.langgraph.checkpoint.base.BaseCheckpointSaver;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Asynchronous in-memory implementation of a checkpoint saver.
+ * This is a thin wrapper around the synchronous implementation that
+ * executes operations asynchronously.
+ */
+public class AsyncMemoryCheckpointSaver implements AsyncBaseCheckpointSaver {
+    private final BaseCheckpointSaver synchronousSaver;
+    
+    /**
+     * Create an async memory checkpoint saver.
+     */
+    public AsyncMemoryCheckpointSaver() {
+        this.synchronousSaver = new MemoryCheckpointSaver();
+    }
+    
+    /**
+     * Create an async memory checkpoint saver with an existing synchronous saver.
+     *
+     * @param synchronousSaver The synchronous checkpoint saver to wrap
+     */
+    public AsyncMemoryCheckpointSaver(BaseCheckpointSaver synchronousSaver) {
+        this.synchronousSaver = synchronousSaver;
+    }
+    
+    @Override
+    public CompletableFuture<String> checkpointAsync(String threadId, Map<String, Object> channelValues) {
+        return CompletableFuture.supplyAsync(() -> 
+            synchronousSaver.checkpoint(threadId, channelValues));
+    }
+    
+    @Override
+    public CompletableFuture<Optional<Map<String, Object>>> getValuesAsync(String checkpointId) {
+        return CompletableFuture.supplyAsync(() -> 
+            synchronousSaver.getValues(checkpointId));
+    }
+    
+    @Override
+    public CompletableFuture<List<String>> listAsync(String threadId) {
+        return CompletableFuture.supplyAsync(() -> 
+            synchronousSaver.list(threadId));
+    }
+    
+    @Override
+    public CompletableFuture<Optional<String>> latestAsync(String threadId) {
+        return CompletableFuture.supplyAsync(() -> 
+            synchronousSaver.latest(threadId));
+    }
+    
+    @Override
+    public CompletableFuture<Void> deleteAsync(String checkpointId) {
+        return CompletableFuture.runAsync(() -> 
+            synchronousSaver.delete(checkpointId));
+    }
+    
+    @Override
+    public CompletableFuture<Void> clearAsync(String threadId) {
+        return CompletableFuture.runAsync(() -> 
+            synchronousSaver.clear(threadId));
+    }
+    
+    /**
+     * Get the underlying synchronous checkpoint saver.
+     *
+     * @return The synchronous checkpoint saver
+     */
+    public BaseCheckpointSaver getSynchronousSaver() {
+        return synchronousSaver;
+    }
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/base/memory/MemoryCheckpointSaver.java

@@ -0,0 +1,77 @@
+package com.langgraph.checkpoint.base.memory;
+
+import com.langgraph.checkpoint.base.BaseCheckpointSaver;
+import com.langgraph.checkpoint.base.ID;
+
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * In-memory implementation of a checkpoint saver.
+ */
+public class MemoryCheckpointSaver implements BaseCheckpointSaver {
+    private final Map<String, Map<String, Object>> checkpoints = new ConcurrentHashMap<>();
+    private final Map<String, List<String>> threadCheckpoints = new ConcurrentHashMap<>();
+    
+    @Override
+    public String checkpoint(String threadId, Map<String, Object> channelValues) {
+        String checkpointId = ID.checkpointId(threadId);
+        
+        // Store the checkpoint
+        checkpoints.put(checkpointId, new HashMap<>(channelValues));
+        
+        // Add to thread's checkpoints
+        threadCheckpoints.computeIfAbsent(threadId, k -> 
+            Collections.synchronizedList(new ArrayList<>())).add(checkpointId);
+        
+        return checkpointId;
+    }
+    
+    @Override
+    public Optional<Map<String, Object>> getValues(String checkpointId) {
+        Map<String, Object> values = checkpoints.get(checkpointId);
+        return Optional.ofNullable(values).map(HashMap::new);
+    }
+    
+    @Override
+    public List<String> list(String threadId) {
+        List<String> result = threadCheckpoints.get(threadId);
+        return result != null ? new ArrayList<>(result) : Collections.emptyList();
+    }
+    
+    @Override
+    public Optional<String> latest(String threadId) {
+        List<String> checkpoints = threadCheckpoints.get(threadId);
+        
+        if (checkpoints == null || checkpoints.isEmpty()) {
+            return Optional.empty();
+        }
+        
+        return Optional.of(checkpoints.get(checkpoints.size() - 1));
+    }
+    
+    @Override
+    public void delete(String checkpointId) {
+        // Remove the checkpoint
+        Map<String, Object> removed = checkpoints.remove(checkpointId);
+        
+        if (removed != null) {
+            // Find and remove from thread's checkpoints
+            for (List<String> checkpointsList : threadCheckpoints.values()) {
+                checkpointsList.remove(checkpointId);
+            }
+        }
+    }
+    
+    @Override
+    public void clear(String threadId) {
+        List<String> checkpointIds = threadCheckpoints.remove(threadId);
+        
+        if (checkpointIds != null) {
+            // Remove all checkpoints for this thread
+            for (String checkpointId : checkpointIds) {
+                checkpoints.remove(checkpointId);
+            }
+        }
+    }
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/serde/MsgPackSerializer.java

@@ -0,0 +1,548 @@
+package com.langgraph.checkpoint.serde;
+
+import org.msgpack.core.MessageBufferPacker;
+import org.msgpack.core.MessagePack;
+import org.msgpack.core.MessageUnpacker;
+import org.msgpack.core.MessageFormat;
+
+import java.io.IOException;
+import java.lang.reflect.*;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * MessagePack-based serializer that uses reflection to handle arbitrary Java objects.
+ * Supports primitive types, collections, maps, records, and custom objects.
+ */
+public class MsgPackSerializer implements ReflectionSerializer {
+    private final Map<Class<?>, TypeSerializer<?>> serializers = new ConcurrentHashMap<>();
+    private final Map<Class<?>, TypeDeserializer<?>> deserializers = new ConcurrentHashMap<>();
+    private final Map<Class<?>, RecordInfo> recordInfoCache = new ConcurrentHashMap<>();
+    
+    /**
+     * Record component information cache to avoid repeated reflection.
+     */
+    private static class RecordInfo {
+        final RecordComponent[] components;
+        final Constructor<?> constructor;
+        
+        RecordInfo(RecordComponent[] components, Constructor<?> constructor) {
+            this.components = components;
+            this.constructor = constructor;
+        }
+    }
+    
+    /**
+     * Register built-in serializers for common types.
+     */
+    public MsgPackSerializer() {
+        registerBuiltinTypes();
+    }
+    
+    /**
+     * Register built-in serializers for common types.
+     */
+    private void registerBuiltinTypes() {
+        // UUID serializer
+        registerSerializer(UUID.class, (uuid) -> uuid.toString());
+        registerDeserializer(UUID.class, (str) -> UUID.fromString((String) str));
+        
+        // Date serializer
+        registerSerializer(java.util.Date.class, (date) -> date.getTime());
+        registerDeserializer(java.util.Date.class, (millis) -> new Date((Long) millis));
+        
+        // Java 8 Date/Time API
+        registerSerializer(Instant.class, (instant) -> instant.toString());
+        registerDeserializer(Instant.class, (str) -> Instant.parse((String) str));
+        
+        registerSerializer(LocalDate.class, (date) -> date.toString());
+        registerDeserializer(LocalDate.class, (str) -> LocalDate.parse((String) str));
+        
+        registerSerializer(LocalTime.class, (time) -> time.toString());
+        registerDeserializer(LocalTime.class, (str) -> LocalTime.parse((String) str));
+        
+        registerSerializer(LocalDateTime.class, (dateTime) -> dateTime.toString());
+        registerDeserializer(LocalDateTime.class, (str) -> LocalDateTime.parse((String) str));
+        
+        // Add more built-in serializers as needed
+    }
+    
+    @Override
+    public <T> void registerSerializer(Class<T> type, TypeSerializer<T> serializer) {
+        serializers.put(type, serializer);
+    }
+    
+    @Override
+    public <T> void registerDeserializer(Class<T> type, TypeDeserializer<T> deserializer) {
+        deserializers.put(type, deserializer);
+    }
+    
+    @Override
+    public byte[] serialize(Object obj) {
+        try {
+            MessageBufferPacker packer = MessagePack.newDefaultBufferPacker();
+            serializeObject(obj, packer);
+            return packer.toByteArray();
+        } catch (IOException e) {
+            throw new SerializationException("Failed to serialize object", e);
+        }
+    }
+    
+    @Override
+    public Object deserialize(byte[] data) {
+        try {
+            MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(data);
+            return deserializeObject(unpacker);
+        } catch (IOException e) {
+            throw new SerializationException("Failed to deserialize object", e);
+        }
+    }
+    
+    /**
+     * Serialize an object to the MessagePack packer.
+     *
+     * @param obj Object to serialize
+     * @param packer MessagePack packer
+     * @throws IOException If packing fails
+     */
+    @SuppressWarnings("unchecked")
+    private void serializeObject(Object obj, MessageBufferPacker packer) throws IOException {
+        if (obj == null) {
+            packer.packNil();
+            return;
+        }
+        
+        Class<?> type = obj.getClass();
+        
+        // Check for registered serializer
+        if (serializers.containsKey(type)) {
+            TypeSerializer<Object> serializer = (TypeSerializer<Object>) serializers.get(type);
+            Object serialized = serializer.toSerializable(obj);
+            
+            // Pack as a special type
+            packer.packMapHeader(2);
+            packer.packString("__type__");
+            packer.packString(type.getName());
+            packer.packString("value");
+            serializeObject(serialized, packer);
+            return;
+        }
+        
+        // Handle primitive types and common objects directly
+        if (obj instanceof String) {
+            packer.packString((String) obj);
+        } else if (obj instanceof Integer) {
+            packer.packInt((Integer) obj);
+        } else if (obj instanceof Long) {
+            packer.packLong((Long) obj);
+        } else if (obj instanceof Double) {
+            packer.packDouble((Double) obj);
+        } else if (obj instanceof Float) {
+            packer.packFloat((Float) obj);
+        } else if (obj instanceof Boolean) {
+            packer.packBoolean((Boolean) obj);
+        } else if (obj instanceof byte[]) {
+            packer.packBinaryHeader(((byte[]) obj).length);
+            packer.writePayload((byte[]) obj);
+        } else if (obj instanceof List) {
+            List<?> list = (List<?>) obj;
+            packer.packArrayHeader(list.size());
+            for (Object item : list) {
+                serializeObject(item, packer);
+            }
+        } else if (obj instanceof Map) {
+            Map<?, ?> map = (Map<?, ?>) obj;
+            packer.packMapHeader(map.size());
+            for (Map.Entry<?, ?> entry : map.entrySet()) {
+                serializeObject(entry.getKey(), packer);
+                serializeObject(entry.getValue(), packer);
+            }
+        } else if (obj instanceof Enum<?>) {
+            // Handle enums by name
+            packer.packMapHeader(2);
+            packer.packString("__type__");
+            packer.packString(type.getName());
+            packer.packString("value");
+            packer.packString(((Enum<?>) obj).name());
+        } else if (type.isRecord()) {
+            // Handle Record types
+            serializeRecord(obj, packer);
+        } else {
+            // Handle custom objects with reflection
+            serializeCustomObject(obj, packer);
+        }
+    }
+    
+    /**
+     * Serialize a Record object.
+     *
+     * @param record The record to serialize
+     * @param packer The MessagePack packer
+     * @throws IOException If packing fails
+     */
+    private void serializeRecord(Object record, MessageBufferPacker packer) throws IOException {
+        Class<?> recordClass = record.getClass();
+        
+        // Pack as a special type with fields
+        packer.packMapHeader(2);
+        packer.packString("__type__");
+        packer.packString(recordClass.getName());
+        packer.packString("fields");
+        
+        RecordComponent[] components = recordClass.getRecordComponents();
+        packer.packMapHeader(components.length);
+        
+        for (RecordComponent component : components) {
+            packer.packString(component.getName());
+            try {
+                Method accessor = component.getAccessor();
+                Object value = accessor.invoke(record);
+                serializeObject(value, packer);
+            } catch (ReflectiveOperationException e) {
+                throw new SerializationException("Failed to access record component: " + component.getName(), e);
+            }
+        }
+    }
+    
+    /**
+     * Serialize a custom object using reflection.
+     *
+     * @param obj The object to serialize
+     * @param packer The MessagePack packer
+     * @throws IOException If packing fails
+     */
+    private void serializeCustomObject(Object obj, MessageBufferPacker packer) throws IOException {
+        Class<?> objClass = obj.getClass();
+        
+        // Pack as a special type with fields
+        packer.packMapHeader(2);
+        packer.packString("__type__");
+        packer.packString(objClass.getName());
+        packer.packString("fields");
+        
+        // Get all fields including inherited ones
+        List<Field> fields = getAllFields(objClass);
+        
+        // Filter out transient fields
+        List<Field> serializableFields = fields.stream()
+            .filter(field -> !Modifier.isTransient(field.getModifiers()) && 
+                            !Modifier.isStatic(field.getModifiers()))
+            .toList();
+        
+        packer.packMapHeader(serializableFields.size());
+        
+        for (Field field : serializableFields) {
+            packer.packString(field.getName());
+            try {
+                field.setAccessible(true);
+                Object value = field.get(obj);
+                serializeObject(value, packer);
+            } catch (IllegalAccessException e) {
+                throw new SerializationException("Failed to access field: " + field.getName(), e);
+            }
+        }
+    }
+    
+    /**
+     * Get all fields for a class including inherited fields.
+     *
+     * @param clazz The class to get fields for
+     * @return List of all fields
+     */
+    private List<Field> getAllFields(Class<?> clazz) {
+        List<Field> fields = new ArrayList<>();
+        Class<?> currentClass = clazz;
+        
+        while (currentClass != null && currentClass != Object.class) {
+            fields.addAll(Arrays.asList(currentClass.getDeclaredFields()));
+            currentClass = currentClass.getSuperclass();
+        }
+        
+        return fields;
+    }
+    
+    /**
+     * Deserialize an object from the MessagePack unpacker.
+     *
+     * @param unpacker MessagePack unpacker
+     * @return Deserialized object
+     * @throws IOException If unpacking fails
+     */
+    @SuppressWarnings("unchecked")
+    private Object deserializeObject(MessageUnpacker unpacker) throws IOException {
+        if (!unpacker.hasNext()) {
+            throw new SerializationException("Unexpected end of data");
+        }
+        
+        if (unpacker.tryUnpackNil()) {
+            return null;
+        }
+        
+        MessageFormat format = unpacker.getNextFormat();
+        
+        if (format == MessageFormat.STR8 || 
+            format == MessageFormat.STR16 || 
+            format == MessageFormat.STR32 || 
+            format == MessageFormat.FIXSTR) {
+            return unpacker.unpackString();
+        } else if (format == MessageFormat.INT8 || 
+                  format == MessageFormat.INT16 || 
+                  format == MessageFormat.INT32 || 
+                  format == MessageFormat.INT64 || 
+                  format == MessageFormat.UINT8 || 
+                  format == MessageFormat.UINT16 || 
+                  format == MessageFormat.UINT32 || 
+                  format == MessageFormat.UINT64 || 
+                  format == MessageFormat.POSFIXINT || 
+                  format == MessageFormat.NEGFIXINT) {
+            if (format == MessageFormat.INT64 || format == MessageFormat.UINT64) {
+                return unpacker.unpackLong();
+            } else {
+                try {
+                    return unpacker.unpackInt();
+                } catch (Exception e) {
+                    // Fallback to long if int unpacking fails
+                    return unpacker.unpackLong();
+                }
+            }
+        } else if (format == MessageFormat.FLOAT32 || 
+                  format == MessageFormat.FLOAT64) {
+            return unpacker.unpackDouble();
+        } else if (format == MessageFormat.BOOLEAN) {
+            return unpacker.unpackBoolean();
+        } else if (format == MessageFormat.BIN8 || 
+                  format == MessageFormat.BIN16 || 
+                  format == MessageFormat.BIN32) {
+            int binaryLength = unpacker.unpackBinaryHeader();
+            byte[] binary = new byte[binaryLength];
+            unpacker.readPayload(binary);
+            return binary;
+        } else if (format == MessageFormat.ARRAY16 || 
+                  format == MessageFormat.ARRAY32 || 
+                  format == MessageFormat.FIXARRAY) {
+            int arraySize = unpacker.unpackArrayHeader();
+            List<Object> list = new ArrayList<>(arraySize);
+            for (int i = 0; i < arraySize; i++) {
+                list.add(deserializeObject(unpacker));
+            }
+            return list;
+        } else if (format == MessageFormat.MAP16 || 
+                  format == MessageFormat.MAP32 || 
+                  format == MessageFormat.FIXMAP) {
+            int mapSize = unpacker.unpackMapHeader();
+            
+            // Handle empty map
+            if (mapSize == 0) {
+                return new HashMap<>();
+            }
+            
+            // Check for special type marker
+            Object firstKey = deserializeObject(unpacker);
+            if (mapSize == 2 && firstKey instanceof String && "__type__".equals(firstKey)) {
+                String typeName = (String) deserializeObject(unpacker);
+                
+                // Get the second key
+                Object secondKey = deserializeObject(unpacker);
+                
+                if (secondKey instanceof String) {
+                    String secondKeyStr = (String) secondKey;
+                    
+                    try {
+                        Class<?> type = Class.forName(typeName);
+                        
+                        // Check for registered deserializer
+                        if ("value".equals(secondKeyStr) && deserializers.containsKey(type)) {
+                            Object serialized = deserializeObject(unpacker);
+                            TypeDeserializer<Object> deserializer = 
+                                (TypeDeserializer<Object>) deserializers.get(type);
+                            return deserializer.fromSerialized(serialized);
+                        }
+                        
+                        // Handle enums
+                        if ("value".equals(secondKeyStr) && type.isEnum()) {
+                            String enumValue = (String) deserializeObject(unpacker);
+                            return Enum.valueOf((Class<Enum>) type, enumValue);
+                        }
+                        
+                        // Handle records
+                        if ("fields".equals(secondKeyStr) && type.isRecord()) {
+                            return deserializeRecord(type, unpacker);
+                        }
+                        
+                        // Handle custom objects
+                        if ("fields".equals(secondKeyStr)) {
+                            return deserializeCustomObject(type, unpacker);
+                        }
+                    } catch (ClassNotFoundException e) {
+                        // If class not found, fall back to regular map deserialization
+                    } catch (ReflectiveOperationException e) {
+                        throw new SerializationException("Failed to deserialize object of type " + typeName, e);
+                    }
+                    
+                    // If special type handling failed, read the value to keep unpacker consistent
+                    Object secondValue = deserializeObject(unpacker);
+                    
+                    // Create a fallback map with the special type info
+                    Map<Object, Object> fallbackMap = new HashMap<>();
+                    fallbackMap.put(firstKey, typeName);
+                    fallbackMap.put(secondKey, secondValue);
+                    return fallbackMap;
+                }
+                
+                // If the second key wasn't a string as expected, we need to handle it as a regular map
+                Object firstValue = deserializeObject(unpacker);
+                
+                // Create a map with the first key-value pair
+                Map<Object, Object> map = new HashMap<>(mapSize);
+                map.put(firstKey, firstValue);
+                
+                // Read the remaining entries
+                for (int i = 1; i < mapSize; i++) {
+                    Object key = deserializeObject(unpacker);
+                    Object value = deserializeObject(unpacker);
+                    map.put(key, value);
+                }
+                
+                return map;
+            } else {
+                // Regular map - we already read the first key
+                Map<Object, Object> map = new HashMap<>(mapSize);
+                
+                // Read the first value
+                Object firstValue = deserializeObject(unpacker);
+                map.put(firstKey, firstValue);
+                
+                // Read the remaining entries
+                for (int i = 1; i < mapSize; i++) {
+                    Object key = deserializeObject(unpacker);
+                    Object value = deserializeObject(unpacker);
+                    map.put(key, value);
+                }
+                
+                return map;
+            }
+        }
+        
+        // Default case
+        throw new SerializationException("Unsupported MessagePack format: " + format);
+    }
+    
+    /**
+     * Deserialize a record.
+     *
+     * @param recordClass The record class
+     * @param unpacker The unpacker containing the fields map
+     * @return The deserialized record
+     * @throws IOException If unpacking fails
+     * @throws ReflectiveOperationException If reflection operations fail
+     */
+    private Object deserializeRecord(Class<?> recordClass, MessageUnpacker unpacker) 
+            throws IOException, ReflectiveOperationException {
+        
+        // Get record info from cache or create it
+        RecordInfo recordInfo = recordInfoCache.computeIfAbsent(recordClass, cls -> {
+            try {
+                RecordComponent[] components = cls.getRecordComponents();
+                Class<?>[] paramTypes = Arrays.stream(components)
+                    .map(RecordComponent::getType)
+                    .toArray(Class<?>[]::new);
+                Constructor<?> constructor = cls.getDeclaredConstructor(paramTypes);
+                constructor.setAccessible(true);
+                return new RecordInfo(components, constructor);
+            } catch (NoSuchMethodException e) {
+                throw new SerializationException("Failed to get constructor for record: " + cls.getName(), e);
+            }
+        });
+        
+        // Read the fields map
+        int fieldCount = unpacker.unpackMapHeader();
+        Map<String, Object> fieldValues = new HashMap<>(fieldCount);
+        
+        for (int i = 0; i < fieldCount; i++) {
+            String fieldName = (String) deserializeObject(unpacker);
+            Object fieldValue = deserializeObject(unpacker);
+            fieldValues.put(fieldName, fieldValue);
+        }
+        
+        // Prepare constructor arguments in the correct order
+        Object[] constructorArgs = new Object[recordInfo.components.length];
+        for (int i = 0; i < recordInfo.components.length; i++) {
+            RecordComponent component = recordInfo.components[i];
+            Object value = fieldValues.get(component.getName());
+            constructorArgs[i] = value;
+        }
+        
+        // Create the record instance
+        return recordInfo.constructor.newInstance(constructorArgs);
+    }
+    
+    /**
+     * Deserialize a custom object.
+     *
+     * @param objectClass The object class
+     * @param unpacker The unpacker containing the fields map
+     * @return The deserialized object
+     * @throws IOException If unpacking fails
+     * @throws ReflectiveOperationException If reflection operations fail
+     */
+    private Object deserializeCustomObject(Class<?> objectClass, MessageUnpacker unpacker) 
+            throws IOException, ReflectiveOperationException {
+        
+        // Create instance using default constructor
+        Constructor<?> constructor;
+        try {
+            constructor = objectClass.getDeclaredConstructor();
+            constructor.setAccessible(true);
+        } catch (NoSuchMethodException e) {
+            throw new SerializationException(
+                "Class " + objectClass.getName() + " must have a no-arg constructor for deserialization", e);
+        }
+        
+        Object instance = constructor.newInstance();
+        
+        // Read the fields map
+        int fieldCount = unpacker.unpackMapHeader();
+        
+        for (int i = 0; i < fieldCount; i++) {
+            String fieldName = (String) deserializeObject(unpacker);
+            Object fieldValue = deserializeObject(unpacker);
+            
+            try {
+                // Find the field (including in superclasses)
+                Field field = findField(objectClass, fieldName);
+                if (field != null) {
+                    field.setAccessible(true);
+                    field.set(instance, fieldValue);
+                }
+            } catch (NoSuchFieldException e) {
+                // Skip fields that don't exist in the current class version
+            }
+        }
+        
+        return instance;
+    }
+    
+    /**
+     * Find a field in a class or its superclasses.
+     *
+     * @param clazz The class to search
+     * @param fieldName The field name to find
+     * @return The found field
+     * @throws NoSuchFieldException If the field is not found
+     */
+    private Field findField(Class<?> clazz, String fieldName) throws NoSuchFieldException {
+        Class<?> currentClass = clazz;
+        while (currentClass != null) {
+            try {
+                return currentClass.getDeclaredField(fieldName);
+            } catch (NoSuchFieldException e) {
+                currentClass = currentClass.getSuperclass();
+            }
+        }
+        throw new NoSuchFieldException("Field not found: " + fieldName);
+    }
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/serde/ReflectionSerializer.java

@@ -0,0 +1,24 @@
+package com.langgraph.checkpoint.serde;
+
+/**
+ * Interface for a serializer that uses reflection to handle arbitrary Java objects.
+ */
+public interface ReflectionSerializer extends Serializer<Object> {
+    /**
+     * Register a custom serializer for a specific type.
+     *
+     * @param type Type to register
+     * @param serializer Custom serializer for the type
+     * @param <T> Type to register
+     */
+    <T> void registerSerializer(Class<T> type, TypeSerializer<T> serializer);
+    
+    /**
+     * Register a custom deserializer for a specific type.
+     *
+     * @param type Type to register
+     * @param deserializer Custom deserializer for the type
+     * @param <T> Type to register
+     */
+    <T> void registerDeserializer(Class<T> type, TypeDeserializer<T> deserializer);
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/serde/SerializationException.java

@@ -0,0 +1,25 @@
+package com.langgraph.checkpoint.serde;
+
+/**
+ * Exception thrown during serialization/deserialization.
+ */
+public class SerializationException extends RuntimeException {
+    /**
+     * Create a new serialization exception with a message.
+     *
+     * @param message Error message
+     */
+    public SerializationException(String message) {
+        super(message);
+    }
+    
+    /**
+     * Create a new serialization exception with a message and cause.
+     *
+     * @param message Error message
+     * @param cause Underlying cause
+     */
+    public SerializationException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/serde/Serializer.java

@@ -0,0 +1,24 @@
+package com.langgraph.checkpoint.serde;
+
+/**
+ * Interface for serializing and deserializing objects.
+ * 
+ * @param <T> Type of object to serialize/deserialize
+ */
+public interface Serializer<T> {
+    /**
+     * Serialize an object to bytes.
+     *
+     * @param obj The object to serialize
+     * @return Serialized bytes
+     */
+    byte[] serialize(T obj);
+    
+    /**
+     * Deserialize bytes to an object.
+     *
+     * @param data The bytes to deserialize
+     * @return Deserialized object
+     */
+    T deserialize(byte[] data);
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/serde/TypeDeserializer.java

@@ -0,0 +1,17 @@
+package com.langgraph.checkpoint.serde;
+
+/**
+ * Interface for deserializing a specific type from MessagePack.
+ *
+ * @param <T> Type to deserialize
+ */
+@FunctionalInterface
+public interface TypeDeserializer<T> {
+    /**
+     * Convert from serialized representation to object.
+     *
+     * @param serialized Serialized representation
+     * @return Deserialized object
+     */
+    T fromSerialized(Object serialized);
+}

langgraph-java/langgraph-checkpoint/src/main/java/com/langgraph/checkpoint/serde/TypeSerializer.java

@@ -0,0 +1,17 @@
+package com.langgraph.checkpoint.serde;
+
+/**
+ * Interface for serializing a specific type to a format that can be included in MessagePack.
+ *
+ * @param <T> Type to serialize
+ */
+@FunctionalInterface
+public interface TypeSerializer<T> {
+    /**
+     * Convert object to a serializable representation.
+     *
+     * @param obj Object to convert
+     * @return Serializable representation (must be compatible with MessagePack)
+     */
+    Object toSerializable(T obj);
+}

langgraph-java/langgraph-checkpoint/src/test/java/com/langgraph/checkpoint/base/IDTest.java

@@ -0,0 +1,59 @@
+package com.langgraph.checkpoint.base;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class IDTest {
+
+    @Test
+    public void testUuidDeterministic() {
+        // Same inputs should produce same UUIDs
+        UUID uuid1 = ID.uuid("test", "value");
+        UUID uuid2 = ID.uuid("test", "value");
+        
+        assertThat(uuid1).isEqualTo(uuid2);
+    }
+    
+    @Test
+    public void testUuidDifferentNamespace() {
+        // Different namespaces should produce different UUIDs
+        UUID uuid1 = ID.uuid("namespace1", "value");
+        UUID uuid2 = ID.uuid("namespace2", "value");
+        
+        assertThat(uuid1).isNotEqualTo(uuid2);
+    }
+    
+    @Test
+    public void testUuidDifferentName() {
+        // Different names should produce different UUIDs
+        UUID uuid1 = ID.uuid("test", "value1");
+        UUID uuid2 = ID.uuid("test", "value2");
+        
+        assertThat(uuid1).isNotEqualTo(uuid2);
+    }
+    
+    @Test
+    public void testCheckpointId() {
+        // Checkpoint IDs should be valid UUIDs
+        String id = ID.checkpointId("thread-123");
+        
+        // Should be a valid UUID string
+        UUID uuid = UUID.fromString(id);
+        assertThat(uuid).isNotNull();
+    }
+    
+    @Test
+    public void testUrlSafeId() {
+        // URL-safe IDs should be deterministic
+        String id1 = ID.urlSafeId("test", "value");
+        String id2 = ID.urlSafeId("test", "value");
+        
+        assertThat(id1).isEqualTo(id2);
+        
+        // Should not contain padding characters or unsafe URL characters
+        assertThat(id1).doesNotContain("=", "+", "/");
+    }
+}

langgraph-java/langgraph-checkpoint/src/test/java/com/langgraph/checkpoint/base/memory/AsyncMemoryCheckpointSaverTest.java

@@ -0,0 +1,155 @@
+package com.langgraph.checkpoint.base.memory;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class AsyncMemoryCheckpointSaverTest {
+    
+    private AsyncMemoryCheckpointSaver saver;
+    
+    @BeforeEach
+    public void setUp() {
+        saver = new AsyncMemoryCheckpointSaver();
+    }
+    
+    @Test
+    public void testCheckpointAsync() throws ExecutionException, InterruptedException {
+        // Create test data
+        String threadId = "test-thread";
+        Map<String, Object> values = new HashMap<>();
+        values.put("key1", "value1");
+        values.put("key2", 42);
+        
+        // Create checkpoint asynchronously
+        CompletableFuture<String> future = saver.checkpointAsync(threadId, values);
+        
+        // Wait for completion
+        String checkpointId = future.get();
+        
+        // Verify checkpoint ID format (should be a UUID)
+        assertThat(checkpointId).matches("^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$");
+        
+        // Verify thread has a checkpoint
+        CompletableFuture<List<String>> listFuture = saver.listAsync(threadId);
+        List<String> checkpoints = listFuture.get();
+        assertThat(checkpoints).hasSize(1);
+        assertThat(checkpoints).contains(checkpointId);
+    }
+    
+    @Test
+    public void testGetValuesAsync() throws ExecutionException, InterruptedException {
+        // Create test data
+        String threadId = "test-thread";
+        Map<String, Object> values = new HashMap<>();
+        values.put("key1", "value1");
+        values.put("key2", 42);
+        
+        // Create checkpoint
+        String checkpointId = saver.checkpointAsync(threadId, values).get();
+        
+        // Get values asynchronously
+        CompletableFuture<Optional<Map<String, Object>>> future = saver.getValuesAsync(checkpointId);
+        Optional<Map<String, Object>> retrievedValues = future.get();
+        
+        // Verify values
+        assertThat(retrievedValues).isPresent();
+        assertThat(retrievedValues.get()).containsEntry("key1", "value1");
+        assertThat(retrievedValues.get()).containsEntry("key2", 42);
+    }
+    
+    @Test
+    public void testListAsync() throws ExecutionException, InterruptedException {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Initially empty
+        CompletableFuture<List<String>> initialFuture = saver.listAsync(threadId);
+        List<String> initial = initialFuture.get();
+        assertThat(initial).isEmpty();
+        
+        // Create multiple checkpoints
+        String id1 = saver.checkpointAsync(threadId, Map.of("key", "value1")).get();
+        String id2 = saver.checkpointAsync(threadId, Map.of("key", "value2")).get();
+        String id3 = saver.checkpointAsync(threadId, Map.of("key", "value3")).get();
+        
+        // List checkpoints asynchronously
+        CompletableFuture<List<String>> future = saver.listAsync(threadId);
+        List<String> checkpoints = future.get();
+        
+        // Verify order and content
+        assertThat(checkpoints).hasSize(3);
+        assertThat(checkpoints).containsExactly(id1, id2, id3);
+    }
+    
+    @Test
+    public void testLatestAsync() throws ExecutionException, InterruptedException {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Initially empty
+        CompletableFuture<Optional<String>> initialFuture = saver.latestAsync(threadId);
+        Optional<String> initial = initialFuture.get();
+        assertThat(initial).isEmpty();
+        
+        // Create multiple checkpoints
+        saver.checkpointAsync(threadId, Map.of("key", "value1")).get();
+        saver.checkpointAsync(threadId, Map.of("key", "value2")).get();
+        String id3 = saver.checkpointAsync(threadId, Map.of("key", "value3")).get();
+        
+        // Get latest asynchronously
+        CompletableFuture<Optional<String>> future = saver.latestAsync(threadId);
+        Optional<String> latest = future.get();
+        
+        // Verify latest
+        assertThat(latest).isPresent();
+        assertThat(latest.get()).isEqualTo(id3);
+    }
+    
+    @Test
+    public void testDeleteAsync() throws ExecutionException, InterruptedException {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Create checkpoint
+        String checkpointId = saver.checkpointAsync(threadId, Map.of("key", "value")).get();
+        
+        // Verify checkpoint exists
+        assertThat(saver.getValuesAsync(checkpointId).get()).isPresent();
+        
+        // Delete checkpoint asynchronously
+        CompletableFuture<Void> future = saver.deleteAsync(checkpointId);
+        future.get(); // Wait for completion
+        
+        // Verify checkpoint is deleted
+        assertThat(saver.getValuesAsync(checkpointId).get()).isEmpty();
+    }
+    
+    @Test
+    public void testClearAsync() throws ExecutionException, InterruptedException {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Create multiple checkpoints
+        String id1 = saver.checkpointAsync(threadId, Map.of("key", "value1")).get();
+        String id2 = saver.checkpointAsync(threadId, Map.of("key", "value2")).get();
+        
+        // Verify checkpoints exist
+        assertThat(saver.listAsync(threadId).get()).hasSize(2);
+        
+        // Clear thread asynchronously
+        CompletableFuture<Void> future = saver.clearAsync(threadId);
+        future.get(); // Wait for completion
+        
+        // Verify checkpoints are deleted
+        assertThat(saver.listAsync(threadId).get()).isEmpty();
+    }
+}

langgraph-java/langgraph-checkpoint/src/test/java/com/langgraph/checkpoint/base/memory/MemoryCheckpointSaverTest.java

@@ -0,0 +1,161 @@
+package com.langgraph.checkpoint.base.memory;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class MemoryCheckpointSaverTest {
+    
+    private MemoryCheckpointSaver saver;
+    
+    @BeforeEach
+    public void setUp() {
+        saver = new MemoryCheckpointSaver();
+    }
+    
+    @Test
+    public void testCheckpoint() {
+        // Create test data
+        String threadId = "test-thread";
+        Map<String, Object> values = new HashMap<>();
+        values.put("key1", "value1");
+        values.put("key2", 42);
+        
+        // Create checkpoint
+        String checkpointId = saver.checkpoint(threadId, values);
+        
+        // Verify checkpoint ID format (should be a UUID)
+        assertThat(checkpointId).matches("^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$");
+        
+        // Verify thread has a checkpoint
+        List<String> checkpoints = saver.list(threadId);
+        assertThat(checkpoints).hasSize(1);
+        assertThat(checkpoints).contains(checkpointId);
+        
+        // Verify latest checkpoint
+        Optional<String> latest = saver.latest(threadId);
+        assertThat(latest).isPresent();
+        assertThat(latest.get()).isEqualTo(checkpointId);
+    }
+    
+    @Test
+    public void testGetValues() {
+        // Create test data
+        String threadId = "test-thread";
+        Map<String, Object> values = new HashMap<>();
+        values.put("key1", "value1");
+        values.put("key2", 42);
+        
+        // Create checkpoint
+        String checkpointId = saver.checkpoint(threadId, values);
+        
+        // Get values
+        Optional<Map<String, Object>> retrievedValues = saver.getValues(checkpointId);
+        
+        // Verify values
+        assertThat(retrievedValues).isPresent();
+        assertThat(retrievedValues.get()).containsEntry("key1", "value1");
+        assertThat(retrievedValues.get()).containsEntry("key2", 42);
+        
+        // Verify non-existent checkpoint
+        Optional<Map<String, Object>> nonExistent = saver.getValues("non-existent");
+        assertThat(nonExistent).isEmpty();
+    }
+    
+    @Test
+    public void testList() {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Initially empty
+        List<String> initial = saver.list(threadId);
+        assertThat(initial).isEmpty();
+        
+        // Create multiple checkpoints
+        String id1 = saver.checkpoint(threadId, Map.of("key", "value1"));
+        String id2 = saver.checkpoint(threadId, Map.of("key", "value2"));
+        String id3 = saver.checkpoint(threadId, Map.of("key", "value3"));
+        
+        // List checkpoints
+        List<String> checkpoints = saver.list(threadId);
+        
+        // Verify order and content
+        assertThat(checkpoints).hasSize(3);
+        assertThat(checkpoints).containsExactly(id1, id2, id3);
+        
+        // Different thread should have no checkpoints
+        List<String> otherThread = saver.list("other-thread");
+        assertThat(otherThread).isEmpty();
+    }
+    
+    @Test
+    public void testLatest() {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Initially empty
+        Optional<String> initial = saver.latest(threadId);
+        assertThat(initial).isEmpty();
+        
+        // Create multiple checkpoints
+        saver.checkpoint(threadId, Map.of("key", "value1"));
+        saver.checkpoint(threadId, Map.of("key", "value2"));
+        String id3 = saver.checkpoint(threadId, Map.of("key", "value3"));
+        
+        // Get latest
+        Optional<String> latest = saver.latest(threadId);
+        
+        // Verify latest
+        assertThat(latest).isPresent();
+        assertThat(latest.get()).isEqualTo(id3);
+    }
+    
+    @Test
+    public void testDelete() {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Create checkpoint
+        String checkpointId = saver.checkpoint(threadId, Map.of("key", "value"));
+        
+        // Verify checkpoint exists
+        assertThat(saver.getValues(checkpointId)).isPresent();
+        assertThat(saver.list(threadId)).contains(checkpointId);
+        
+        // Delete checkpoint
+        saver.delete(checkpointId);
+        
+        // Verify checkpoint is deleted
+        assertThat(saver.getValues(checkpointId)).isEmpty();
+        assertThat(saver.list(threadId)).doesNotContain(checkpointId);
+    }
+    
+    @Test
+    public void testClear() {
+        // Create test data
+        String threadId = "test-thread";
+        
+        // Create multiple checkpoints
+        String id1 = saver.checkpoint(threadId, Map.of("key", "value1"));
+        String id2 = saver.checkpoint(threadId, Map.of("key", "value2"));
+        
+        // Verify checkpoints exist
+        assertThat(saver.list(threadId)).hasSize(2);
+        assertThat(saver.getValues(id1)).isPresent();
+        assertThat(saver.getValues(id2)).isPresent();
+        
+        // Clear thread
+        saver.clear(threadId);
+        
+        // Verify checkpoints are deleted
+        assertThat(saver.list(threadId)).isEmpty();
+        assertThat(saver.getValues(id1)).isEmpty();
+        assertThat(saver.getValues(id2)).isEmpty();
+    }
+}

langgraph-java/langgraph-checkpoint/src/test/java/com/langgraph/checkpoint/serde/MsgPackSerializerTest.java

@@ -0,0 +1,383 @@
+package com.langgraph.checkpoint.serde;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.util.*;
+import java.util.Objects;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.within;
+
+public class MsgPackSerializerTest {
+    
+    private MsgPackSerializer serializer;
+    
+    @BeforeEach
+    public void setUp() {
+        serializer = new MsgPackSerializer();
+    }
+    
+    @Test
+    public void testSerializeDeserializePrimitives() {
+        // Test with various primitive types
+        assertRoundTrip("Test string");
+        assertRoundTrip(123);
+        assertRoundTrip(123456789L);
+        assertRoundTrip(123.45);
+        assertRoundTrip(123.45f);
+        assertRoundTrip(true);
+        assertRoundTrip(false);
+        assertRoundTrip(null);
+    }
+    
+    @Test
+    public void testSerializeDeserializeArrays() {
+        // Test with arrays and collections
+        assertRoundTrip(new byte[] {1, 2, 3, 4, 5});
+        assertRoundTrip(Arrays.asList("one", "two", "three"));
+        assertRoundTrip(Arrays.asList(1, 2, 3, 4, 5));
+    }
+    
+    @Test
+    public void testSerializeDeserializeMaps() {
+        // Test with maps
+        Map<String, Object> map = new HashMap<>();
+        map.put("string", "value");
+        map.put("int", 123);
+        map.put("boolean", true);
+        
+        assertRoundTrip(map);
+    }
+    
+    @Test
+    public void testSerializeDeserializeNestedStructures() {
+        // Test with nested structures
+        Map<String, Object> nested = new HashMap<>();
+        nested.put("list", Arrays.asList(1, 2, 3));
+        nested.put("map", Map.of("key", "value"));
+        
+        assertRoundTrip(nested);
+    }
+    
+    @Test
+    public void testSerializeDeserializeEnums() {
+        // Test with enums
+        assertRoundTrip(TestEnum.VALUE1);
+        assertRoundTrip(TestEnum.VALUE2);
+        assertRoundTrip(TestEnum.VALUE3);
+    }
+    
+    @Test
+    public void testSerializeDeserializeRecord() {
+        // Test with a record
+        TestRecord record = new TestRecord("test", 123, Arrays.asList("a", "b", "c"));
+        
+        // Serialize and deserialize
+        byte[] serialized = serializer.serialize(record);
+        Object deserialized = serializer.deserialize(serialized);
+        
+        // Verify
+        assertThat(deserialized).isInstanceOf(TestRecord.class);
+        TestRecord deserializedRecord = (TestRecord) deserialized;
+        assertThat(deserializedRecord.name()).isEqualTo("test");
+        assertThat(deserializedRecord.value()).isEqualTo(123);
+        assertThat(deserializedRecord.tags()).containsExactly("a", "b", "c");
+    }
+    
+    @Test
+    public void testSerializeDeserializeNestedRecord() {
+        // Test with a nested record
+        NestedTestRecord record = new NestedTestRecord(
+            "parent", 
+            new TestRecord("child", 456, Arrays.asList("x", "y", "z"))
+        );
+        
+        // Serialize and deserialize
+        byte[] serialized = serializer.serialize(record);
+        Object deserialized = serializer.deserialize(serialized);
+        
+        // Verify
+        assertThat(deserialized).isInstanceOf(NestedTestRecord.class);
+        NestedTestRecord deserializedRecord = (NestedTestRecord) deserialized;
+        assertThat(deserializedRecord.name()).isEqualTo("parent");
+        assertThat(deserializedRecord.child()).isInstanceOf(TestRecord.class);
+        assertThat(deserializedRecord.child().name()).isEqualTo("child");
+        assertThat(deserializedRecord.child().value()).isEqualTo(456);
+        assertThat(deserializedRecord.child().tags()).containsExactly("x", "y", "z");
+    }
+    
+    @Test
+    public void testSerializeDeserializeCustomObject() {
+        // Test with a custom object
+        TestObject obj = new TestObject();
+        obj.setName("test");
+        obj.setValue(123);
+        obj.setActive(true);
+        
+        // Serialize and deserialize
+        byte[] serialized = serializer.serialize(obj);
+        Object deserialized = serializer.deserialize(serialized);
+        
+        // Verify
+        assertThat(deserialized).isInstanceOf(TestObject.class);
+        TestObject deserializedObj = (TestObject) deserialized;
+        assertThat(deserializedObj.getName()).isEqualTo("test");
+        assertThat(deserializedObj.getValue()).isEqualTo(123);
+        assertThat(deserializedObj.isActive()).isTrue();
+    }
+    
+    @Test
+    public void testSerializeDeserializeInheritance() {
+        // Test with inheritance
+        ChildTestObject obj = new ChildTestObject();
+        obj.setName("parent");
+        obj.setValue(123);
+        obj.setActive(true);
+        obj.setChildProperty("child");
+        obj.setChildValue(456);
+        
+        // Serialize and deserialize
+        byte[] serialized = serializer.serialize(obj);
+        Object deserialized = serializer.deserialize(serialized);
+        
+        // Verify
+        assertThat(deserialized).isInstanceOf(ChildTestObject.class);
+        ChildTestObject deserializedObj = (ChildTestObject) deserialized;
+        assertThat(deserializedObj.getName()).isEqualTo("parent");
+        assertThat(deserializedObj.getValue()).isEqualTo(123);
+        assertThat(deserializedObj.isActive()).isTrue();
+        assertThat(deserializedObj.getChildProperty()).isEqualTo("child");
+        assertThat(deserializedObj.getChildValue()).isEqualTo(456);
+    }
+    
+    @Test
+    public void testSerializeDeserializeWithCustomSerializer() {
+        // Register custom UUID serializer (although built-in one exists)
+        serializer.registerSerializer(UUID.class, (uuid) -> uuid.toString().replace("-", ""));
+        serializer.registerDeserializer(UUID.class, (str) -> {
+            String uuidStr = (String) str;
+            // Insert hyphens for standard UUID format
+            uuidStr = uuidStr.replaceFirst(
+                    "(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)",
+                    "$1-$2-$3-$4-$5");
+            return UUID.fromString(uuidStr);
+        });
+        
+        // Test with UUID
+        UUID uuid = UUID.randomUUID();
+        
+        // Serialize and deserialize
+        byte[] serialized = serializer.serialize(uuid);
+        Object deserialized = serializer.deserialize(serialized);
+        
+        // Verify
+        assertThat(deserialized).isInstanceOf(UUID.class);
+        assertThat(deserialized).isEqualTo(uuid);
+    }
+    
+    @Test
+    public void testSerializeDeserializeDateTypes() {
+        // Test with Date
+        Date date = new Date();
+        
+        // Serialize and deserialize
+        byte[] serialized = serializer.serialize(date);
+        Object deserialized = serializer.deserialize(serialized);
+        
+        // Verify
+        assertThat(deserialized).isInstanceOf(Date.class);
+        assertThat(deserialized).isEqualTo(date);
+        
+        // Test with Java 8 Date/Time types
+        Instant instant = Instant.now();
+        LocalDate localDate = LocalDate.now();
+        LocalTime localTime = LocalTime.now();
+        LocalDateTime localDateTime = LocalDateTime.now();
+        
+        assertRoundTrip(instant);
+        assertRoundTrip(localDate);
+        assertRoundTrip(localTime);
+        assertRoundTrip(localDateTime);
+    }
+    
+    @Test
+    public void testTransientFields() {
+        // Test with transient fields
+        ObjectWithTransient obj = new ObjectWithTransient();
+        obj.setPersistent("saved");
+        obj.setTransientField("not-saved");
+        
+        // Serialize and deserialize
+        byte[] serialized = serializer.serialize(obj);
+        Object deserialized = serializer.deserialize(serialized);
+        
+        // Verify
+        assertThat(deserialized).isInstanceOf(ObjectWithTransient.class);
+        ObjectWithTransient deserializedObj = (ObjectWithTransient) deserialized;
+        assertThat(deserializedObj.getPersistent()).isEqualTo("saved");
+        assertThat(deserializedObj.getTransientField()).isNull(); // Should be null after deserialization
+    }
+    
+    /**
+     * Helper method to assert that an object survives a round trip through serialization.
+     *
+     * @param obj Object to test
+     */
+    private void assertRoundTrip(Object obj) {
+        try {
+            // Serialize
+            byte[] serialized = serializer.serialize(obj);
+            
+            // Deserialize
+            Object deserialized = serializer.deserialize(serialized);
+            
+            // Verify
+            if (obj instanceof byte[]) {
+                // Arrays need special comparison
+                assertThat(deserialized).isInstanceOf(byte[].class);
+                assertThat((byte[]) deserialized).isEqualTo((byte[]) obj);
+            } else if (obj instanceof Number) {
+                // For any number type, compare by value instead of exact type
+                if (deserialized instanceof Number) {
+                    double expected = ((Number) obj).doubleValue();
+                    double actual = ((Number) deserialized).doubleValue();
+                    assertThat(actual).isCloseTo(expected, within(0.0001));
+                } else {
+                    throw new AssertionError("Expected Number, got " + 
+                        (deserialized != null ? deserialized.getClass().getName() : "null"));
+                }
+            } else {
+                // Special handling for lists
+                if (obj instanceof List && deserialized instanceof List) {
+                    List<?> originalList = (List<?>) obj;
+                    List<?> deserializedList = (List<?>) deserialized;
+                    assertThat(deserializedList).hasSameSizeAs(originalList);
+                    
+                    // Check each element
+                    for (int i = 0; i < originalList.size(); i++) {
+                        Object originalItem = originalList.get(i);
+                        Object deserializedItem = deserializedList.get(i);
+                        
+                        if (originalItem instanceof Number && deserializedItem instanceof Number) {
+                            // Compare numbers by value instead of exact type
+                            assertThat(((Number) deserializedItem).doubleValue())
+                                .isCloseTo(((Number) originalItem).doubleValue(), within(0.0001));
+                        } else {
+                            assertThat(deserializedItem).isEqualTo(originalItem);
+                        }
+                    }
+                } else {
+                    // Regular equality for other types
+                    assertThat(deserialized).isEqualTo(obj);
+                }
+            }
+        } catch (Exception e) {
+            throw new AssertionError("Error in roundtrip for " + obj + ": " + e.getMessage(), e);
+        }
+    }
+    
+    /**
+     * Test enum.
+     */
+    public enum TestEnum {
+        VALUE1, VALUE2, VALUE3
+    }
+    
+    /**
+     * Test record class.
+     */
+    public record TestRecord(String name, int value, List<String> tags) {
+    }
+    
+    /**
+     * Nested test record class.
+     */
+    public record NestedTestRecord(String name, TestRecord child) {
+    }
+    
+    /**
+     * Test class for custom object serialization.
+     */
+    public static class TestObject {
+        private String name;
+        private int value;
+        private boolean active;
+        
+        public String getName() {
+            return name;
+        }
+        
+        public void setName(String name) {
+            this.name = name;
+        }
+        
+        public int getValue() {
+            return value;
+        }
+        
+        public void setValue(int value) {
+            this.value = value;
+        }
+        
+        public boolean isActive() {
+            return active;
+        }
+        
+        public void setActive(boolean active) {
+            this.active = active;
+        }
+    }
+    
+    /**
+     * Child test class for inheritance testing.
+     */
+    public static class ChildTestObject extends TestObject {
+        private String childProperty;
+        private int childValue;
+        
+        public String getChildProperty() {
+            return childProperty;
+        }
+        
+        public void setChildProperty(String childProperty) {
+            this.childProperty = childProperty;
+        }
+        
+        public int getChildValue() {
+            return childValue;
+        }
+        
+        public void setChildValue(int childValue) {
+            this.childValue = childValue;
+        }
+    }
+    
+    /**
+     * Test class with transient fields.
+     */
+    public static class ObjectWithTransient {
+        private String persistent;
+        private transient String transientField;
+        
+        public String getPersistent() {
+            return persistent;
+        }
+        
+        public void setPersistent(String persistent) {
+            this.persistent = persistent;
+        }
+        
+        public String getTransientField() {
+            return transientField;
+        }
+        
+        public void setTransientField(String transientField) {
+            this.transientField = transientField;
+        }
+    }
+}

langgraph-java/settings.gradle

@@ -0,0 +1,5 @@
+rootProject.name = 'langgraph-java'
+
+include 'langgraph-checkpoint'
+include 'langgraph-core'
+include 'langgraph-examples'