diff --git a/.gitignore b/.gitignore
index 52a0cca..43b0b22 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,4 @@ build/*
 *.jar
 build
 .gradle
+*.txt
diff --git a/README.md b/README.md
index bf63ccb..cf19210 100644
--- a/README.md
+++ b/README.md
@@ -132,14 +132,43 @@ java -jar j3270.jar -d mainframe.example.com
 
 ## 🛠️ Building from Source
 
-### Standalone Build (No Gradle Required)
-The project provides self-contained, portable build scripts requiring only a JDK:
+### Quick Setup & Build for End Users
+
+Self-contained setup scripts automatically locate an installed Java 11+ JDK (searching `JAVA_HOME`, system `PATH`, macOS `java_home`, Homebrew, Linux JVM paths, Windows Registry, standard installation directories, and package managers), compile `lib3270j` and `j3270`, and package the standalone executable JAR (`build/j3270.jar`):
+
+**Linux / macOS (POSIX Shell):**
+```bash
+# Setup and build standalone executable JAR:
+./setup.sh
+
+# Build and immediately launch:
+./setup.sh --run
+
+# Clean build and connect to host:
+./setup.sh --clean --run -- mainframe.example.com 23 4
+```
+
+**Windows (PowerShell):**
+```powershell
+# Setup and build standalone executable JAR:
+.\setup.ps1
+
+# Build and immediately launch:
+.\setup.ps1 -Run
+
+# Clean build and connect to host:
+.\setup.ps1 -Clean -Run -- mainframe.example.com 23 4
+```
+*(Also available as `.\setup.ps`)*
+
+### Standalone Build (Advanced / CI)
+The project also provides low-level scripts and optional Gradle support:
 
 ```bash
-# Build standalone executable JAR (build/j3270.jar):
+# Direct compile and package without diagnostics:
 sh ./build_all.sh
 
-# Run all 539 automated unit tests across 88 test containers (~7s):
+# Run all 539+ automated unit tests (~7s):
 sh ./test_all.sh
 ```
 
diff --git a/build.gradle b/build.gradle
index 8330c48..0b6bdc6 100644
--- a/build.gradle
+++ b/build.gradle
@@ -17,6 +17,7 @@ subprojects {
 
     test {
         useJUnitPlatform()
+        jvmArgs '-Djava.awt.headless=true'
         testLogging {
             events "passed", "skipped", "failed"
         }
@@ -24,5 +25,6 @@ subprojects {
 
     dependencies {
         testImplementation 'org.junit.jupiter:junit-jupiter:5.10.2'
+        testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
     }
 }
diff --git a/build_all.sh b/build_all.sh
index 061e89a..72be89e 100755
--- a/build_all.sh
+++ b/build_all.sh
@@ -14,16 +14,32 @@ if [ -n "$JAVA_HOME" ] && [ -x "$JAVA_HOME/bin/javac" ] && [ -x "$JAVA_HOME/bin/
     JAVAC_BIN="$JAVA_HOME/bin/javac"
     JAR_BIN="$JAVA_HOME/bin/jar"
 elif command -v javac >/dev/null 2>&1 && command -v jar >/dev/null 2>&1; then
-    JAVAC_BIN="$(command -v javac)"
-    JAR_BIN="$(command -v jar)"
-else
-    # Check common SDKMAN / macOS / Linux JDK locations
-    for h in "$HOME/.sdkman/candidates/java/current" \
+    if javac -version >/dev/null 2>&1; then
+        JAVAC_BIN="$(command -v javac)"
+        JAR_BIN="$(command -v jar)"
+    fi
+fi
+
+if [ -z "$JAVAC_BIN" ] || [ -z "$JAR_BIN" ]; then
+    if [ -x /usr/libexec/java_home ]; then
+        MAC_JAVA_HOME="$(/usr/libexec/java_home 2>/dev/null || true)"
+        if [ -n "$MAC_JAVA_HOME" ] && [ -x "$MAC_JAVA_HOME/bin/javac" ] && [ -x "$MAC_JAVA_HOME/bin/jar" ]; then
+            export JAVA_HOME="$MAC_JAVA_HOME"
+            JAVAC_BIN="$JAVA_HOME/bin/javac"
+            JAR_BIN="$JAVA_HOME/bin/jar"
+        fi
+    fi
+fi
+
+if [ -z "$JAVAC_BIN" ] || [ -z "$JAR_BIN" ]; then
+    # Check standard system JDK installation locations
+    for h in /usr/lib/jvm/default-java \
              /usr/lib/jvm/java-21-openjdk* \
              /usr/lib/jvm/java-17-openjdk* \
              /usr/lib/jvm/java-11-openjdk* \
-             /usr/lib/jvm/default-java \
-             /Library/Java/JavaVirtualMachines/*/Contents/Home; do
+             /Library/Java/JavaVirtualMachines/*/Contents/Home \
+             /opt/homebrew/opt/openjdk/libexec/openjdk.jdk/Contents/Home \
+             /opt/homebrew/opt/openjdk; do
         if [ -d "$h" ] && [ -x "$h/bin/javac" ] && [ -x "$h/bin/jar" ]; then
             export JAVA_HOME="$h"
             JAVAC_BIN="$JAVA_HOME/bin/javac"
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 1af9e09..37f78a6 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.3.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
diff --git a/gradlew b/gradlew
index 49bef16..1aa94a4 100755
--- a/gradlew
+++ b/gradlew
@@ -1,2 +1,249 @@
 #!/bin/sh
-exec "$(dirname "$0")/build_all.sh" "$@"
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..6689b85
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,92 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+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/lib3270j/src/test/java/haus/nightmare/lib3270j/integration/LiveHostHeadlessTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/integration/LiveHostHeadlessTest.java
index 1bd58ef..49e59ec 100644
--- a/lib3270j/src/test/java/haus/nightmare/lib3270j/integration/LiveHostHeadlessTest.java
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/integration/LiveHostHeadlessTest.java
@@ -112,4 +112,48 @@ public class LiveHostHeadlessTest {
             client.disconnect();
         }
     }
+
+    @Test
+    @DisplayName("Logon to live MVS host with guest account 'headless'")
+    public void testLiveMvsGuestLogin() throws Exception {
+        boolean reachable = false;
+        try (Socket probe = new Socket()) {
+            probe.connect(new InetSocketAddress(HOST, PORT), 3000);
+            reachable = true;
+        } catch (IOException e) {
+            logger.warning("Live host " + HOST + ":" + PORT + " unreachable: " + e.getMessage());
+        }
+
+        Assumptions.assumeTrue(reachable, "Skipping live test: " + HOST + ":" + PORT + " is not reachable");
+
+        ConnectionConfig config = new ConnectionConfig(HOST, PORT, TerminalModel.IBM_3279_2);
+        config.setConnectTimeoutMs(5000);
+        config.setSoTimeoutMs(10000);
+
+        Telnet3270Client client = new Telnet3270Client(config);
+        try {
+            boolean connected = client.connect(10000);
+            Assumptions.assumeTrue(connected, "Host connection established");
+
+            // Wait for initial screen buffer to populate
+            Thread.sleep(1500);
+            ScreenBuffer sb = client.getScreenBuffer();
+            String initialText = sb != null ? sb.getText().trim() : "";
+            logger.info("Initial screen before logon: " +
+                    initialText.substring(0, Math.min(150, initialText.length())).replaceAll("\\s+", " "));
+
+            // Send guest account 'headless'
+            client.sendKeys("headless[enter]");
+            Thread.sleep(2000);
+
+            String responseText = sb != null ? sb.getText().trim() : "";
+            logger.info("Screen after typing 'headless': " +
+                    responseText.substring(0, Math.min(150, responseText.length())).replaceAll("\\s+", " "));
+
+            assertNotNull(responseText, "Screen response should not be null");
+            assertFalse(responseText.isEmpty(), "Screen response should not be empty");
+        } finally {
+            client.disconnect();
+        }
+    }
 }
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/testutil/Mock3270Server.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/testutil/Mock3270Server.java
new file mode 100644
index 0000000..51af59d
--- /dev/null
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/testutil/Mock3270Server.java
@@ -0,0 +1,570 @@
+package haus.nightmare.lib3270j.testutil;
+
+import haus.nightmare.lib3270j.charset.EbcdicTranslator;
+import haus.nightmare.lib3270j.protocol.DS3270Constants;
+import haus.nightmare.lib3270j.protocol.TN3270EConstants;
+import haus.nightmare.lib3270j.protocol.TelnetConstants;
+
+import java.io.*;
+import java.net.*;
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
+import static haus.nightmare.lib3270j.protocol.TN3270EConstants.*;
+import static haus.nightmare.lib3270j.protocol.TelnetConstants.*;
+
+/**
+ * Lightweight, in-memory mock TN3270E server running on loopback (127.0.0.1).
+ *
+ * Implements RFC 2355 Telnet negotiation, Device-Type subnegotiation,
+ * BIND image dispatch, formatted 3270 data stream framing (Write / Erase-Write),
+ * Contention Resolution (SDI / KRI), Keep-Alive tracking, and disconnect simulation.
+ */
+public class Mock3270Server implements AutoCloseable {
+
+    private static final Logger log = Logger.getLogger(Mock3270Server.class.getName());
+
+    private final ServerSocket serverSocket;
+    private final int port;
+    private final EbcdicTranslator translator;
+    private final ExecutorService executor = Executors.newCachedThreadPool(r -> {
+        Thread t = new Thread(r, "Mock3270Server-Worker");
+        t.setDaemon(true);
+        return t;
+    });
+
+    private volatile boolean running = true;
+    private volatile Socket currentSocket;
+    private volatile OutputStream clientOut;
+    private volatile InputStream clientIn;
+
+    private boolean negotiateBindImage = true;
+    private boolean negotiateContentionResolution = true;
+    private boolean autoSendBind = true;
+    private String assignedDeviceType = "IBM-3279-2-E";
+    private String assignedLu = "MOCKLU01";
+    private int primaryRows = 24;
+    private int primaryCols = 80;
+    private int altRows = 24;
+    private int altCols = 80;
+    private int sequenceNumber = 0;
+
+    private final List<byte[]> receivedRecords = new CopyOnWriteArrayList<>();
+    private final AtomicInteger receivedNops = new AtomicInteger(0);
+    private final AtomicInteger receivedTimingMarks = new AtomicInteger(0);
+
+    private volatile CountDownLatch connectionLatch = new CountDownLatch(1);
+    private volatile CountDownLatch handshakeLatch = new CountDownLatch(1);
+    private volatile CountDownLatch dataReceivedLatch = new CountDownLatch(1);
+
+    public Mock3270Server() throws IOException {
+        this(0);
+    }
+
+    public Mock3270Server(int requestedPort) throws IOException {
+        this.serverSocket = new ServerSocket(requestedPort, 10, InetAddress.getByName("127.0.0.1"));
+        this.port = serverSocket.getLocalPort();
+        this.translator = new EbcdicTranslator();
+        executor.submit(this::acceptLoop);
+        log.info("Mock3270Server started on 127.0.0.1:" + port);
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+    public void setNegotiateBindImage(boolean negotiate) {
+        this.negotiateBindImage = negotiate;
+    }
+
+    public void setNegotiateContentionResolution(boolean cr) {
+        this.negotiateContentionResolution = cr;
+    }
+
+    public void setAutoSendBind(boolean autoSendBind) {
+        this.autoSendBind = autoSendBind;
+    }
+
+    public void setAssignedDeviceType(String assignedDeviceType) {
+        this.assignedDeviceType = assignedDeviceType;
+    }
+
+    public void setAssignedLu(String assignedLu) {
+        this.assignedLu = assignedLu;
+    }
+
+    public void setDimensions(int pRows, int pCols, int aRows, int aCols) {
+        this.primaryRows = pRows;
+        this.primaryCols = pCols;
+        this.altRows = aRows;
+        this.altCols = aCols;
+    }
+
+    public boolean waitForConnection(long timeout, TimeUnit unit) throws InterruptedException {
+        if (currentSocket != null && currentSocket.isConnected() && !currentSocket.isClosed()) {
+            return true;
+        }
+        return connectionLatch.await(timeout, unit);
+    }
+
+    public boolean waitForHandshake(long timeout, TimeUnit unit) throws InterruptedException {
+        return handshakeLatch.await(timeout, unit);
+    }
+
+    public boolean waitForClientData(long timeout, TimeUnit unit) throws InterruptedException {
+        if (!receivedRecords.isEmpty()) {
+            return true;
+        }
+        return dataReceivedLatch.await(timeout, unit);
+    }
+
+    public List<byte[]> getReceivedRecords() {
+        return Collections.unmodifiableList(receivedRecords);
+    }
+
+    public byte[] getLastReceivedRecord() {
+        if (receivedRecords.isEmpty()) return null;
+        return receivedRecords.get(receivedRecords.size() - 1);
+    }
+
+    public int getReceivedNops() {
+        return receivedNops.get();
+    }
+
+    public int getReceivedTimingMarks() {
+        return receivedTimingMarks.get();
+    }
+
+    public void resetDataLatch() {
+        dataReceivedLatch = new CountDownLatch(1);
+    }
+
+    private void acceptLoop() {
+        while (running) {
+            try {
+                Socket s = serverSocket.accept();
+                s.setTcpNoDelay(true);
+                log.info("Mock3270Server: accepted client connection from " + s.getRemoteSocketAddress());
+                synchronized (this) {
+                    this.currentSocket = s;
+                    this.clientIn = new BufferedInputStream(s.getInputStream());
+                    this.clientOut = new BufferedOutputStream(s.getOutputStream());
+                }
+                connectionLatch.countDown();
+                executor.submit(() -> handleClient(s));
+            } catch (SocketException e) {
+                if (!running) break;
+            } catch (Exception e) {
+                if (running) {
+                    log.log(Level.WARNING, "Error in acceptLoop", e);
+                }
+            }
+        }
+    }
+
+    private void handleClient(Socket s) {
+        try {
+            // 1. Initial Telnet option offer
+            sendInitialNegotiation();
+
+            // 2. Read incoming telnet options and data loop
+            ByteArrayOutputStream recordBuf = new ByteArrayOutputStream();
+            ByteArrayOutputStream sbBuf = new ByteArrayOutputStream();
+            int b;
+            boolean inIAC = false;
+            int iacCommand = -1;
+            boolean inSB = false;
+
+            while (running && !s.isClosed() && (b = clientIn.read()) != -1) {
+                b &= 0xFF;
+
+                if (inSB) {
+                    if (inIAC) {
+                        if (b == SE) {
+                            inSB = false;
+                            inIAC = false;
+                            handleSubnegotiation(sbBuf.toByteArray());
+                            sbBuf.reset();
+                        } else if (b == IAC) {
+                            sbBuf.write(IAC);
+                            inIAC = false;
+                        } else {
+                            inIAC = false;
+                        }
+                    } else if (b == IAC) {
+                        inIAC = true;
+                    } else {
+                        sbBuf.write(b);
+                    }
+                    continue;
+                }
+
+                if (inIAC) {
+                    if (iacCommand == -1) {
+                        iacCommand = b;
+                        switch (b) {
+                            case IAC: // Escaped 0xFF in data stream
+                                recordBuf.write(IAC);
+                                inIAC = false;
+                                iacCommand = -1;
+                                break;
+                            case SB:
+                                inSB = true;
+                                inIAC = false;
+                                iacCommand = -1;
+                                sbBuf.reset();
+                                break;
+                            case EOR:
+                                // End of record framing
+                                byte[] fullRecord = recordBuf.toByteArray();
+                                recordBuf.reset();
+                                inIAC = false;
+                                iacCommand = -1;
+                                onRecordReceived(fullRecord);
+                                break;
+                            case NOP:
+                                receivedNops.incrementAndGet();
+                                log.fine("Mock3270Server: RCVD IAC NOP");
+                                inIAC = false;
+                                iacCommand = -1;
+                                break;
+                            case DO:
+                            case DONT:
+                            case WILL:
+                            case WONT:
+                                // Option follows next byte
+                                break;
+                            default:
+                                inIAC = false;
+                                iacCommand = -1;
+                                break;
+                        }
+                    } else {
+                        // 3-byte command: IAC <DO/DONT/WILL/WONT> <OPT>
+                        handleOptionCommand(iacCommand, b);
+                        inIAC = false;
+                        iacCommand = -1;
+                    }
+                } else if (b == IAC) {
+                    inIAC = true;
+                    iacCommand = -1;
+                } else {
+                    recordBuf.write(b);
+                }
+            }
+        } catch (SocketException e) {
+            log.fine("Client socket closed: " + e.getMessage());
+        } catch (Exception e) {
+            if (running) {
+                log.log(Level.WARNING, "Error in handleClient", e);
+            }
+        } finally {
+            cleanupClientSocket(s);
+        }
+    }
+
+    private synchronized void sendInitialNegotiation() throws IOException {
+        if (clientOut == null) return;
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        // Server offers DO TN3270E, DO TRANSMIT-BINARY, WILL TRANSMIT-BINARY, DO EOR, WILL EOR
+        out.write(new byte[] {
+            (byte) IAC, (byte) DO, (byte) TELOPT_TN3270E,
+            (byte) IAC, (byte) DO, (byte) TELOPT_BINARY,
+            (byte) IAC, (byte) WILL, (byte) TELOPT_BINARY,
+            (byte) IAC, (byte) DO, (byte) TELOPT_EOR,
+            (byte) IAC, (byte) WILL, (byte) TELOPT_EOR
+        });
+        clientOut.write(out.toByteArray());
+        clientOut.flush();
+        log.info("Mock3270Server: sent initial negotiation");
+    }
+
+    private void handleOptionCommand(int cmd, int opt) throws IOException {
+        log.fine("Mock3270Server: RCVD IAC " + cmd + " opt=" + opt);
+        if (cmd == WILL && opt == TELOPT_TN3270E) {
+            // Client accepted TN3270E -> Send SB TN3270E SEND DEVICE-TYPE IAC SE
+            sendDeviceTypeSend();
+        } else if (cmd == DO && opt == TELOPT_TM) {
+            // Client requested Timing Mark keep-alive
+            receivedTimingMarks.incrementAndGet();
+            log.fine("Mock3270Server: RCVD IAC DO TIMING-MARK");
+            synchronized (this) {
+                if (clientOut != null) {
+                    clientOut.write(new byte[] { (byte) IAC, (byte) WILL, (byte) TELOPT_TM });
+                    clientOut.flush();
+                }
+            }
+        }
+    }
+
+    private synchronized void sendDeviceTypeSend() throws IOException {
+        if (clientOut == null) return;
+        byte[] devTypeSend = new byte[] {
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            (byte) OP_SEND, (byte) OP_DEVICE_TYPE,
+            (byte) IAC, (byte) SE
+        };
+        clientOut.write(devTypeSend);
+        clientOut.flush();
+        log.info("Mock3270Server: sent SB TN3270E SEND DEVICE-TYPE SE");
+    }
+
+    private void handleSubnegotiation(byte[] sb) throws IOException {
+        if (sb.length < 2 || (sb[0] & 0xFF) != TELOPT_TN3270E) {
+            return;
+        }
+        int op = sb[1] & 0xFF;
+
+        if (op == OP_DEVICE_TYPE) {
+            // Client sent DEVICE-TYPE REQUEST <type> [CONNECT <lu>]
+            int pos = 2;
+            if (pos < sb.length && (sb[pos] & 0xFF) == OP_REQUEST) pos++;
+            StringBuilder reqType = new StringBuilder();
+            while (pos < sb.length && (sb[pos] & 0xFF) != OP_CONNECT) {
+                reqType.append((char) (sb[pos] & 0xFF));
+                pos++;
+            }
+            log.info("Mock3270Server: client requested device-type: " + reqType);
+
+            // Respond with SB TN3270E DEVICE-TYPE IS <assignedType> CONNECT <assignedLu> IAC SE
+            sendDeviceTypeIs(assignedDeviceType, assignedLu);
+
+        } else if (op == OP_FUNCTIONS) {
+            // Client sent FUNCTIONS REQUEST <functions...>
+            List<Integer> funcs = new ArrayList<>();
+            for (int i = 3; i < sb.length; i++) {
+                funcs.add(sb[i] & 0xFF);
+            }
+            log.info("Mock3270Server: client requested functions: " + funcs);
+
+            // Respond with FUNCTIONS IS
+            sendFunctionsIs();
+
+            if (autoSendBind && negotiateBindImage) {
+                sendBindImage();
+            }
+
+            handshakeLatch.countDown();
+        }
+    }
+
+    private synchronized void sendDeviceTypeIs(String type, String lu) throws IOException {
+        if (clientOut == null) return;
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        out.write(new byte[] { (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E, (byte) OP_DEVICE_TYPE, (byte) OP_IS });
+        out.write(type.getBytes(java.nio.charset.StandardCharsets.US_ASCII));
+        if (lu != null && !lu.isEmpty()) {
+            out.write(OP_CONNECT);
+            out.write(lu.getBytes(java.nio.charset.StandardCharsets.US_ASCII));
+        }
+        out.write(new byte[] { (byte) IAC, (byte) SE });
+        clientOut.write(out.toByteArray());
+        clientOut.flush();
+        log.info("Mock3270Server: sent SB TN3270E DEVICE-TYPE IS " + type + " CONNECT " + lu + " SE");
+    }
+
+    private synchronized void sendFunctionsIs() throws IOException {
+        if (clientOut == null) return;
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        out.write(new byte[] { (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E, (byte) OP_FUNCTIONS, (byte) OP_IS });
+        if (negotiateBindImage) {
+            out.write(FUNC_BIND_IMAGE);
+        }
+        out.write(FUNC_RESPONSES);
+        if (negotiateContentionResolution) {
+            out.write(FUNC_CONTENTION_RESOLUTION);
+        }
+        out.write(FUNC_SYSREQ);
+        out.write(new byte[] { (byte) IAC, (byte) SE });
+        clientOut.write(out.toByteArray());
+        clientOut.flush();
+        log.info("Mock3270Server: sent SB TN3270E FUNCTIONS IS SE");
+    }
+
+    public synchronized void sendBindImage() throws IOException {
+        if (clientOut == null) return;
+        // BIND payload: 5-byte header + standard 26-byte BIND image
+        byte[] bindPayload = new byte[26];
+        bindPayload[20] = (byte) primaryRows;
+        bindPayload[21] = (byte) primaryCols;
+        bindPayload[22] = (byte) altRows;
+        bindPayload[23] = (byte) altCols;
+        bindPayload[24] = (byte) ((altRows == primaryRows && altCols == primaryCols) ? 0x02 : 0x7F);
+
+        sendRecord(DT_BIND_IMAGE, 0, RSF_NO_RESPONSE, bindPayload);
+        log.info("Mock3270Server: sent BIND image (" + primaryRows + "x" + primaryCols + " / " + altRows + "x" + altCols + ")");
+    }
+
+    public synchronized void sendUnbind(int reason) throws IOException {
+        sendRecord(DT_UNBIND, 0, RSF_NO_RESPONSE, new byte[] { (byte) reason });
+        log.info("Mock3270Server: sent UNBIND reason=" + reason);
+    }
+
+    public synchronized void sendRecord(int dataType, int requestFlag, int responseFlag, byte[] payload) throws IOException {
+        if (clientOut == null) throw new IOException("No client connected");
+        sequenceNumber = (sequenceNumber + 1) & 0xFFFF;
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream(payload.length + 16);
+        // 5-byte TN3270E header
+        out.write(dataType);
+        out.write(requestFlag);
+        out.write(responseFlag);
+        out.write((sequenceNumber >> 8) & 0xFF);
+        out.write(sequenceNumber & 0xFF);
+
+        // Escape payload IAC (0xFF -> 0xFF 0xFF)
+        for (byte b : payload) {
+            int val = b & 0xFF;
+            out.write(val);
+            if (val == IAC) {
+                out.write(IAC);
+            }
+        }
+
+        // End of Record framing
+        out.write(IAC);
+        out.write(EOR);
+
+        clientOut.write(out.toByteArray());
+        clientOut.flush();
+    }
+
+    public synchronized void sendEraseWrite(int wcc, byte[] data, boolean sdi, boolean kri) throws IOException {
+        ByteArrayOutputStream payload = new ByteArrayOutputStream(data.length + 2);
+        payload.write(CMD_ERASE_WRITE); // 0xF5
+        payload.write(wcc);
+        payload.write(data);
+        int rqf = (sdi ? RQF_SEND_DATA : 0) | (kri ? RQF_KEYBOARD_RESTORE : 0);
+        sendRecord(DT_3270_DATA, rqf, RSF_NO_RESPONSE, payload.toByteArray());
+    }
+
+    public synchronized void sendWrite(int wcc, byte[] data, boolean sdi, boolean kri) throws IOException {
+        ByteArrayOutputStream payload = new ByteArrayOutputStream(data.length + 2);
+        payload.write(CMD_WRITE); // 0xF1
+        payload.write(wcc);
+        payload.write(data);
+        int rqf = (sdi ? RQF_SEND_DATA : 0) | (kri ? RQF_KEYBOARD_RESTORE : 0);
+        sendRecord(DT_3270_DATA, rqf, RSF_NO_RESPONSE, payload.toByteArray());
+    }
+
+    public synchronized void sendFormattedScreen(String text, int row, int col, boolean unlockKeyboard) throws IOException {
+        ByteArrayOutputStream data = new ByteArrayOutputStream();
+        int addr = row * primaryCols + col;
+        byte[] sba = DS3270Constants.encodeAddress(addr, primaryRows, primaryCols);
+
+        // SBA to target position
+        data.write(ORDER_SBA);
+        data.write(sba[0] & 0xFF);
+        data.write(sba[1] & 0xFF);
+
+        // Start Field (unprotected: 0x40 or 0x41)
+        data.write(ORDER_SF);
+        data.write(0x40);
+
+        // Write EBCDIC text
+        for (char c : text.toCharArray()) {
+            data.write(translator.unicodeToEbcdicSafe(c));
+        }
+
+        // Insert Cursor
+        data.write(ORDER_IC);
+
+        // WCC: 0xC3 (sound alarm + unlock keyboard + reset MDT) or 0xC0 (locked)
+        int wcc = unlockKeyboard ? 0xC3 : 0xC0;
+        sendEraseWrite(wcc, data.toByteArray(), true, unlockKeyboard);
+    }
+
+    public synchronized void sendFragmented(byte[] rawData, int chunkSize, long delayMs) throws IOException, InterruptedException {
+        if (clientOut == null) throw new IOException("No client connected");
+        int offset = 0;
+        while (offset < rawData.length) {
+            int len = Math.min(chunkSize, rawData.length - offset);
+            clientOut.write(rawData, offset, len);
+            clientOut.flush();
+            offset += len;
+            if (delayMs > 0 && offset < rawData.length) {
+                Thread.sleep(delayMs);
+            }
+        }
+    }
+
+    public synchronized void sendRawBytes(byte[] raw) throws IOException {
+        if (clientOut == null) throw new IOException("No client connected");
+        clientOut.write(raw);
+        clientOut.flush();
+    }
+
+    public synchronized void disconnectClient() {
+        if (currentSocket != null) {
+            try {
+                log.info("Mock3270Server: intentionally disconnecting client");
+                currentSocket.close();
+            } catch (Exception ignored) {}
+            cleanupClientSocket(currentSocket);
+        }
+    }
+
+    private void onRecordReceived(byte[] record) {
+        log.info("Mock3270Server: received record length=" + record.length);
+        receivedRecords.add(record);
+        dataReceivedLatch.countDown();
+    }
+
+    public int getLastReceivedAID() {
+        byte[] last = getLastReceivedRecord();
+        if (last == null || last.length <= EH_SIZE) return -1;
+        return last[EH_SIZE] & 0xFF;
+    }
+
+    public int getLastReceivedCursorAddress() {
+        byte[] last = getLastReceivedRecord();
+        if (last == null || last.length < EH_SIZE + 3) return -1;
+        int b1 = last[EH_SIZE + 1] & 0xFF;
+        int b2 = last[EH_SIZE + 2] & 0xFF;
+        return DS3270Constants.decodeAddress(b1, b2);
+    }
+
+    public String getLastReceivedFieldText() {
+        byte[] last = getLastReceivedRecord();
+        if (last == null || last.length <= EH_SIZE + 3) return "";
+        StringBuilder sb = new StringBuilder();
+        // Skip header + AID (1) + cursor address (2)
+        int i = EH_SIZE + 3;
+        while (i < last.length) {
+            int b = last[i] & 0xFF;
+            if (b == ORDER_SBA) {
+                i += 3;
+                continue;
+            }
+            sb.append(translator.ebcdicToUnicode(b));
+            i++;
+        }
+        return sb.toString();
+    }
+
+    private synchronized void cleanupClientSocket(Socket s) {
+        if (currentSocket == s) {
+            currentSocket = null;
+            clientIn = null;
+            clientOut = null;
+        }
+        try {
+            s.close();
+        } catch (Exception ignored) {}
+    }
+
+    @Override
+    public void close() {
+        running = false;
+        try {
+            serverSocket.close();
+        } catch (Exception ignored) {}
+        disconnectClient();
+        executor.shutdownNow();
+        log.info("Mock3270Server stopped");
+    }
+}
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/testutil/Mock3270ServerIntegrationTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/testutil/Mock3270ServerIntegrationTest.java
new file mode 100644
index 0000000..7d9e14b
--- /dev/null
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/testutil/Mock3270ServerIntegrationTest.java
@@ -0,0 +1,293 @@
+package haus.nightmare.lib3270j.testutil;
+
+import haus.nightmare.lib3270j.ConnectionConfig;
+import haus.nightmare.lib3270j.ConnectionState;
+import haus.nightmare.lib3270j.Telnet3270Client;
+import haus.nightmare.lib3270j.TerminalModel;
+import haus.nightmare.lib3270j.ecl.ECLConstants;
+import haus.nightmare.lib3270j.ecl.ECLPS;
+import haus.nightmare.lib3270j.ecl.ECLScreenDesc;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
+import static haus.nightmare.lib3270j.protocol.TN3270EConstants.*;
+import static haus.nightmare.lib3270j.protocol.TelnetConstants.*;
+import static org.junit.jupiter.api.Assertions.*;
+
+@Timeout(value = 30, unit = TimeUnit.SECONDS)
+public class Mock3270ServerIntegrationTest {
+
+    private Mock3270Server server;
+    private Telnet3270Client client;
+
+    @BeforeEach
+    public void setup() throws IOException {
+        server = new Mock3270Server();
+    }
+
+    @AfterEach
+    public void teardown() {
+        if (client != null) {
+            client.disconnect();
+            client = null;
+        }
+        if (server != null) {
+            server.close();
+            server = null;
+        }
+    }
+
+    private void waitForState(Telnet3270Client cl, ConnectionState targetState, long timeoutMs) throws Exception {
+        long deadline = System.currentTimeMillis() + timeoutMs;
+        while (System.currentTimeMillis() < deadline) {
+            if (cl.getConnectionState() == targetState) {
+                return;
+            }
+            Thread.sleep(25);
+        }
+        assertEquals(targetState, cl.getConnectionState());
+    }
+
+    @Test
+    public void testSuccessfulConnectionAndHandshake() throws Exception {
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        config.setConnectTimeoutMs(5000);
+        client = new Telnet3270Client(config);
+
+        boolean connected = client.connect(8000);
+        assertTrue(connected, "Client should establish connected session");
+
+        boolean handshakeDone = server.waitForHandshake(5, TimeUnit.SECONDS);
+        assertTrue(handshakeDone, "Mock server should complete TN3270E handshake");
+
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+        assertEquals("MOCKLU01", client.getTelnetFSM().getConnectedLu());
+    }
+
+    @Test
+    public void testSendScreenAndVerifyPresentationSpace() throws Exception {
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        client = new Telnet3270Client(config);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        // Server sends formatted greeting screen at row 2, col 10
+        String banner = "WELCOME TO TN3270E SERVER";
+        server.sendFormattedScreen(banner, 2, 10, true);
+
+        // Wait up to 3s for screen update
+        ECLPS ps = client.getPS();
+        boolean matched = false;
+        long deadline = System.currentTimeMillis() + 3000;
+        while (System.currentTimeMillis() < deadline) {
+            String text = ps.getString(2, 11, banner.length());
+            if (banner.equals(text)) {
+                matched = true;
+                break;
+            }
+            Thread.sleep(20);
+        }
+
+        assertTrue(matched, "Presentation space should contain banner string");
+        assertFalse(client.getInputProcessor().isKeyboardLocked(), "Keyboard should be unlocked after WCC restore");
+    }
+
+    @Test
+    public void testClientUserInputAndAidTransmission() throws Exception {
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        client = new Telnet3270Client(config);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        // Send screen with unprotected field at row 4, col 10
+        server.sendFormattedScreen("ENTER DATA: ", 4, 10, true);
+        Thread.sleep(100);
+
+        // Client positions cursor inside unprotected field (col 23) and enters text
+        client.getPS().setCursorPos(4, 23);
+        client.sendKeys("TESTDATA[enter]");
+
+        // Verify mock server receives AID and field data
+        assertTrue(server.waitForClientData(5, TimeUnit.SECONDS), "Server must receive client AID submission");
+        assertEquals(0x7D, server.getLastReceivedAID(), "AID should be ENTER (0x7D)");
+        assertTrue(server.getLastReceivedFieldText().contains("TESTDATA"),
+                "Field text should contain submitted characters 'TESTDATA'");
+    }
+
+    @Test
+    public void testContentionResolutionAndKeyboardLock() throws Exception {
+        server.setNegotiateContentionResolution(true);
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        client = new Telnet3270Client(config);
+        client.getTelnetFSM().setNegotiateContentionResolution(true);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        // 1. Lock keyboard explicitly (as happens when user presses AID)
+        client.getInputProcessor().setKeyboardLocked(true);
+        assertTrue(client.getInputProcessor().isKeyboardLocked());
+
+        // Send write with WCC locked (0xC0) and sdi = false
+        byte[] dummyData = new byte[] { (byte) ORDER_SBA, 0x40, 0x40, (byte) ORDER_SF, 0x60 };
+        server.sendWrite(0xC0, dummyData, false, false);
+        Thread.sleep(100);
+
+        assertTrue(client.getInputProcessor().isKeyboardLocked(),
+                "Keyboard must remain locked when SDI is not signaled under contention resolution");
+
+        // 2. Unlock via Contention Resolution: send write with SDI flag = true (RQF_SEND_DATA)
+        server.sendWrite(0xC0, dummyData, true, false);
+        Thread.sleep(100);
+
+        assertFalse(client.getInputProcessor().isKeyboardLocked(),
+                "Keyboard must unlock upon receiving SDI flag on EOR");
+    }
+
+    @Test
+    public void testAutoSysUnlockOnEor() throws Exception {
+        server.setNegotiateContentionResolution(false);
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        config.setAutoSysUnlock(true);
+        client = new Telnet3270Client(config);
+        client.getTelnetFSM().setNegotiateContentionResolution(false);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        // Lock keyboard initially
+        client.getInputProcessor().setKeyboardLocked(true);
+        client.getOIA().setInputInhibited(ECLConstants.INHIBIT_SYSTEM_LOCK);
+        assertTrue(client.getInputProcessor().isKeyboardLocked());
+
+        // Host sends a write record without WCC restore, but autoSysUnlock is active on EOR
+        byte[] dummyData = new byte[] { (byte) ORDER_SBA, 0x40, 0x40, (byte) ORDER_SF, 0x60 };
+        server.sendWrite(0xC0, dummyData, false, false);
+        Thread.sleep(100);
+
+        assertFalse(client.getInputProcessor().isKeyboardLocked(),
+                "autoSysUnlock must unlock keyboard on EOR when not in Read command");
+        assertFalse(client.getOIA().isXSystem(), "OIA X SYSTEM indicator must be cleared");
+    }
+
+    @Test
+    public void testAutomatedWaitMethods() throws Exception {
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        client = new Telnet3270Client(config);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        ECLScreenDesc desc = new ECLScreenDesc();
+        desc.addString("LOGIN_READY");
+
+        CountDownLatch waitLatch = new CountDownLatch(1);
+        AtomicBoolean waitResult = new AtomicBoolean(false);
+
+        // Run waitForScreen in background thread
+        CompletableFuture.runAsync(() -> {
+            boolean res = client.getPS().waitForScreen(desc, 5000);
+            waitResult.set(res);
+            waitLatch.countDown();
+        });
+
+        // Delay 80ms then send matching screen from mock server
+        Thread.sleep(80);
+        server.sendFormattedScreen("LOGIN_READY", 1, 9, true);
+
+        boolean awakened = waitLatch.await(2000, TimeUnit.MILLISECONDS);
+        assertTrue(awakened, "waitForScreen must wake reactively upon screen update");
+        assertTrue(waitResult.get(), "waitForScreen must return true when screen matches descriptor");
+    }
+
+    @Test
+    public void testKeepAliveHeartbeatEngine() throws Exception {
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        config.setKeepAliveEnabled(true);
+        config.setKeepAliveIntervalSeconds(1);
+        config.setKeepAliveType("NOP");
+
+        client = new Telnet3270Client(config);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        // Idle for 2.5 seconds to allow keepalive heartbeat to fire
+        Thread.sleep(2500);
+
+        assertTrue(server.getReceivedNops() >= 1,
+                "Server must have received at least 1 IAC NOP heartbeat, received: " + server.getReceivedNops());
+    }
+
+    @Test
+    public void testAutoReconnectOnSocketDisconnect() throws Exception {
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        config.setAutoReconnect(true);
+        config.setReconnectMaxRetries(3);
+
+        client = new Telnet3270Client(config);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        // Disconnect active client connection abruptly
+        server.disconnectClient();
+
+        // Wait for client to detect disconnect and reconnect automatically
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 8000);
+        assertEquals(ConnectionState.CONNECTED_TN3270E, client.getConnectionState());
+    }
+
+    @Test
+    public void testPacketFragmentation() throws Exception {
+        ConnectionConfig config = new ConnectionConfig("127.0.0.1", server.getPort(), TerminalModel.IBM_3279_2);
+        client = new Telnet3270Client(config);
+        assertTrue(client.connect(8000));
+        assertTrue(server.waitForHandshake(5, TimeUnit.SECONDS));
+        waitForState(client, ConnectionState.CONNECTED_TN3270E, 5000);
+
+        // Build raw 3270 Erase/Write packet with 5-byte header + command + SBA + SF + data + IAC EOR
+        ByteArrayOutputStream buf = new ByteArrayOutputStream();
+        // 5-byte header
+        buf.write(new byte[] { (byte) DT_3270_DATA, 0x00, 0x00, 0x00, 0x01 });
+        buf.write(CMD_ERASE_WRITE); // 0xF5
+        buf.write(0xC3); // WCC
+        buf.write(ORDER_SBA);
+        buf.write(0x40); buf.write(0x40); // row 0, col 0
+        buf.write(ORDER_SF);
+        buf.write(0x40); // unprotected
+        String text = "FRAGMENTED_TEST";
+        for (char c : text.toCharArray()) {
+            buf.write(client.getScreenBuffer().getTranslator().unicodeToEbcdicSafe(c));
+        }
+        buf.write((byte) IAC);
+        buf.write((byte) EOR);
+
+        // Send packet in 2-byte fragments with 5ms delays
+        server.sendFragmented(buf.toByteArray(), 2, 5);
+
+        // Verify presentation space renders the entire reconstructed string
+        boolean matched = false;
+        long deadline = System.currentTimeMillis() + 3000;
+        while (System.currentTimeMillis() < deadline) {
+            String read = client.getPS().getString(0, 1, text.length());
+            if (text.equals(read)) {
+                matched = true;
+                break;
+            }
+            Thread.sleep(20);
+        }
+
+        assertTrue(matched, "Fragmented stream must be reassembled and displayed correctly");
+    }
+}
diff --git a/setup.ps b/setup.ps
new file mode 100644
index 0000000..2b8864c
--- /dev/null
+++ b/setup.ps
@@ -0,0 +1,31 @@
+<#
+.SYNOPSIS
+    j3270 Terminal Emulator - Setup and Build Script (PowerShell Entrypoint)
+    Forwards execution directly to setup.ps1 with all supplied parameters.
+
+.DESCRIPTION
+    See setup.ps1 for full implementation, parameter definitions, and documentation.
+#>
+
+[CmdletBinding()]
+param (
+    [switch]$Run,
+    [switch]$Test,
+    [switch]$Clean,
+    [switch]$Help,
+    [Parameter(ValueFromRemainingArguments = $true)]
+    [string[]]$RunArgs
+)
+
+$scriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+if (-not $scriptDir) {
+    $scriptDir = Get-Location
+}
+
+$ps1Script = Join-Path $scriptDir "setup.ps1"
+if (Test-Path $ps1Script) {
+    & $ps1Script @PSBoundParameters @RunArgs
+} else {
+    Write-Error "setup.ps1 not found in $scriptDir"
+    exit 1
+}
diff --git a/setup.ps1 b/setup.ps1
new file mode 100644
index 0000000..53d0df9
--- /dev/null
+++ b/setup.ps1
@@ -0,0 +1,468 @@
+<#
+.SYNOPSIS
+    j3270 Terminal Emulator - Setup and Build Script (PowerShell)
+    Detects Java 11+ JDK and builds j3270 standalone executable JAR.
+
+.DESCRIPTION
+    Searches for a compatible Java Development Kit (JDK 11+ / LTS 11, 17, 21),
+    verifies compiler (javac) and archiver (jar) toolchains, compiles the lib3270j
+    protocol core and j3270 Swing desktop application, and packages the standalone
+    executable JAR file (build/j3270.jar).
+
+.PARAMETER Run
+    Launch j3270 immediately after successful build.
+
+.PARAMETER Test
+    Run unit test suite after successful build.
+
+.PARAMETER Clean
+    Remove previous build artifacts before compiling.
+
+.PARAMETER Help
+    Display usage help message.
+
+.EXAMPLE
+    .\setup.ps1
+    Builds the standalone j3270.jar.
+
+.EXAMPLE
+    .\setup.ps1 -Clean -Run
+    Cleans previous build, builds j3270, and immediately launches the application.
+
+.EXAMPLE
+    .\setup.ps1 -Run -- mainframe.example.com 23 4
+    Builds and connects to specified host, port, and terminal model.
+#>
+
+[CmdletBinding()]
+param (
+    [switch]$Run,
+    [switch]$Test,
+    [switch]$Clean,
+    [switch]$Help,
+    [Parameter(ValueFromRemainingArguments = $true)]
+    [string[]]$RunArgs
+)
+
+$ErrorActionPreference = "Stop"
+
+# Resolve script root directory
+$ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+if (-not $ScriptDir) {
+    $ScriptDir = Get-Location
+}
+Set-Location $ScriptDir
+
+# Helper functions for colored terminal output
+function Write-LogInfo($msg)    { Write-Host "[INFO] $msg" -ForegroundColor Cyan }
+function Write-LogSuccess($msg) { Write-Host "[OK]   $msg" -ForegroundColor Green }
+function Write-LogWarn($msg)    { Write-Host "[WARN] $msg" -ForegroundColor Yellow }
+function Write-LogError($msg)   { Write-Host "[ERROR] $msg" -ForegroundColor Red }
+
+if ($Help) {
+    Write-Host @"
+j3270 Terminal Emulator - Setup & Build Script (PowerShell)
+
+Usage:
+  .\setup.ps1 [-Run] [-Test] [-Clean] [-Help] [-- <run-arguments>]
+
+Options:
+  -Run        Build and immediately launch j3270
+  -Test       Run automated unit tests after build
+  -Clean      Remove previous build artifacts before compiling
+  -Help       Show this help message
+
+Examples:
+  .\setup.ps1
+  .\setup.ps1 -Clean
+  .\setup.ps1 -Run
+  .\setup.ps1 -Run -- mainframe.example.com 23 4
+  .\setup.ps1 -Test
+"@
+    exit 0
+}
+
+Write-Host "`n=== j3270 Setup & Build (PowerShell) ===`n" -ForegroundColor White
+
+# Determine platform
+$isWindows = if (Test-Path variable:IsWindows) { $IsWindows } else { $env:OS -eq "Windows_NT" }
+$exeSuffix = if ($isWindows) { ".exe" } else { "" }
+
+# ------------------------------------------------------------------------------
+# 1. Helper: Parse Major Java Version
+# ------------------------------------------------------------------------------
+function Get-JavaMajorVersion([string]$verStr) {
+    if (-not $verStr) { return 0 }
+    if ($verStr -match 'javac\s+([0-9][0-9._]*)' -or
+        $verStr -match 'version\s+"?([0-9][0-9._]*)"?' -or
+        $verStr -match '([0-9]+(\.[0-9]+)*)') {
+        $token = $matches[1]
+        if ($token -match '^1\.(\d+)') {
+            return [int]$matches[1]
+        }
+        if ($token -match '^(\d+)') {
+            return [int]$matches[1]
+        }
+    }
+    return 0
+}
+
+# ------------------------------------------------------------------------------
+# 2. Helper: Test JDK Candidate Directory
+# ------------------------------------------------------------------------------
+function Test-JdkCandidate([string]$candHome) {
+    if (-not $candHome -or -not (Test-Path $candHome)) {
+        return $null
+    }
+
+    $javacPath = Join-Path $candHome "bin\javac$exeSuffix"
+    $jarPath   = Join-Path $candHome "bin\jar$exeSuffix"
+    $javaPath  = Join-Path $candHome "bin\java$exeSuffix"
+
+    if (-not (Test-Path $javacPath) -or -not (Test-Path $jarPath) -or -not (Test-Path $javaPath)) {
+        return $null
+    }
+
+    try {
+        $pInfo = New-Object System.Diagnostics.ProcessStartInfo
+        $pInfo.FileName = $javacPath
+        $pInfo.Arguments = "-version"
+        $pInfo.RedirectStandardOutput = $true
+        $pInfo.RedirectStandardError = $true
+        $pInfo.UseShellExecute = $false
+        $pInfo.CreateNoWindow = $true
+
+        $proc = [System.Diagnostics.Process]::Start($pInfo)
+        $stdout = $proc.StandardOutput.ReadToEnd()
+        $stderr = $proc.StandardError.ReadToEnd()
+        $proc.WaitForExit()
+
+        if ($proc.ExitCode -eq 0) {
+            $verOutput = ("$stdout $stderr").Trim()
+            $majorVer = Get-JavaMajorVersion $verOutput
+
+            if ($majorVer -ge 11) {
+                return [PSCustomObject]@{
+                    Home    = $candHome
+                    Javac   = $javacPath
+                    Jar     = $jarPath
+                    Java    = $javaPath
+                    Version = $verOutput
+                    Major   = $majorVer
+                }
+            }
+        }
+    } catch {
+        # Process execution failed or access denied
+    }
+
+    return $null
+}
+
+# ------------------------------------------------------------------------------
+# 3. Discover JDK 11+
+# ------------------------------------------------------------------------------
+Write-LogInfo "Searching for a compatible Java Development Kit (JDK 11+)..."
+
+$detectedJdk = $null
+
+# Strategy A: Check JAVA_HOME environment variable
+if ($env:JAVA_HOME) {
+    $detectedJdk = Test-JdkCandidate $env:JAVA_HOME
+    if ($detectedJdk) {
+        Write-LogInfo "Found valid JDK in `$env:JAVA_HOME: $($detectedJdk.Home)"
+    } else {
+        Write-LogWarn "`$env:JAVA_HOME is set ($($env:JAVA_HOME)) but is not a valid JDK 11+."
+    }
+}
+
+# Strategy B: Check current system PATH
+if (-not $detectedJdk) {
+    $pathJavac = Get-Command "javac$exeSuffix" -ErrorAction SilentlyContinue
+    if ($pathJavac) {
+        try {
+            $realPath = $pathJavac.Source
+            $candBin = Split-Path -Parent $realPath
+            $candHome = Split-Path -Parent $candBin
+            $detectedJdk = Test-JdkCandidate $candHome
+            if ($detectedJdk) {
+                Write-LogInfo "Found valid JDK on PATH: $($detectedJdk.Home)"
+            }
+        } catch {}
+    }
+}
+
+# Strategy C: Check Windows Registry (if running on Windows)
+if (-not $detectedJdk -and $isWindows) {
+    $regPaths = @(
+        "HKLM:\SOFTWARE\JavaSoft\JDK",
+        "HKLM:\SOFTWARE\JavaSoft\Java Development Kit",
+        "HKLM:\SOFTWARE\Eclipse Adoptium\JDK",
+        "HKLM:\SOFTWARE\AdoptOpenJDK\JDK",
+        "HKLM:\SOFTWARE\Microsoft\JDK",
+        "HKLM:\SOFTWARE\BellSoft\Liberica JDK",
+        "HKLM:\SOFTWARE\Zulu\zulu-jdk",
+        "HKLM:\SOFTWARE\WOW6432Node\JavaSoft\JDK",
+        "HKLM:\SOFTWARE\WOW6432Node\JavaSoft\Java Development Kit",
+        "HKLM:\SOFTWARE\WOW6432Node\Eclipse Adoptium\JDK",
+        "HKLM:\SOFTWARE\WOW6432Node\Microsoft\JDK"
+    )
+
+    foreach ($regBase in $regPaths) {
+        if (Test-Path $regBase) {
+            $subKeys = Get-ChildItem -Path $regBase -ErrorAction SilentlyContinue
+            foreach ($key in $subKeys) {
+                $item = Get-ItemProperty -Path $key.PSPath -ErrorAction SilentlyContinue
+                if ($item.JavaHome) {
+                    $detectedJdk = Test-JdkCandidate $item.JavaHome
+                    if ($detectedJdk) { break }
+                }
+                if ($item.Path) {
+                    $detectedJdk = Test-JdkCandidate $item.Path
+                    if ($detectedJdk) { break }
+                }
+                # Check hotspot subkey used by Adoptium/Microsoft MSI installers
+                $hotspotKey = Join-Path $key.PSPath "hotspot\MSI"
+                if (Test-Path $hotspotKey) {
+                    $hs = Get-ItemProperty -Path $hotspotKey -ErrorAction SilentlyContinue
+                    if ($hs.Path) {
+                        $detectedJdk = Test-JdkCandidate $hs.Path
+                        if ($detectedJdk) { break }
+                    }
+                }
+            }
+            if ($detectedJdk) {
+                Write-LogInfo "Found valid JDK via Windows Registry: $($detectedJdk.Home)"
+                break
+            }
+        }
+    }
+}
+
+# Strategy D: Check Standard Filesystem Locations
+if (-not $detectedJdk) {
+    $fsCandidates = @()
+
+    if ($isWindows) {
+        $searchRoots = @(
+            "$env:ProgramFiles\Eclipse Adoptium\*",
+            "$env:ProgramFiles\Java\*",
+            "$env:ProgramFiles\Microsoft\*",
+            "$env:ProgramFiles\Amazon Corretto\*",
+            "$env:ProgramFiles\Zulu\*",
+            "$env:ProgramFiles\BellSoft\*",
+            "$env:ProgramFiles\Semeru\*",
+            "$env:ProgramFiles\RedHat\*",
+            "${env:ProgramFiles(x86)}\Java\*",
+            "$env:LOCALAPPDATA\Programs\Eclipse Adoptium\*",
+            "$env:LOCALAPPDATA\Programs\Common\Oracle\Java\*",
+            "$env:USERPROFILE\.jdks\*",
+            "$env:USERPROFILE\.sdkman\candidates\java\*",
+            "$env:USERPROFILE\scoop\apps\openjdk\current",
+            "$env:USERPROFILE\scoop\apps\oraclejdk\current",
+            "$env:USERPROFILE\scoop\apps\temurin\current",
+            "$env:USERPROFILE\scoop\apps\zulu\current",
+            "C:\tools\jdk*",
+            "C:\Java\*"
+        )
+        foreach ($pattern in $searchRoots) {
+            Resolve-Path -Path $pattern -ErrorAction SilentlyContinue | ForEach-Object {
+                $fsCandidates += $_.Path
+            }
+        }
+    } else {
+        # POSIX / macOS search roots for pwsh
+        $searchRoots = @(
+            "/opt/homebrew/opt/openjdk/libexec/openjdk.jdk/Contents/Home",
+            "/opt/homebrew/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home",
+            "/opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home",
+            "/opt/homebrew/opt/openjdk@11/libexec/openjdk.jdk/Contents/Home",
+            "/opt/homebrew/opt/openjdk*",
+            "/usr/local/opt/openjdk/libexec/openjdk.jdk/Contents/Home",
+            "/Library/Java/JavaVirtualMachines/*/Contents/Home",
+            "/usr/lib/jvm/default-java",
+            "/usr/lib/jvm/java-21-openjdk*",
+            "/usr/lib/jvm/java-17-openjdk*",
+            "/usr/lib/jvm/java-11-openjdk*",
+            "/usr/lib/jvm/*",
+            "$env:HOME/.sdkman/candidates/java/current",
+            "$env:HOME/.sdkman/candidates/java/*",
+            "$env:HOME/.asdf/installs/java/*"
+        )
+        foreach ($pattern in $searchRoots) {
+            Resolve-Path -Path $pattern -ErrorAction SilentlyContinue | ForEach-Object {
+                $fsCandidates += $_.Path
+            }
+        }
+    }
+
+    foreach ($cand in $fsCandidates) {
+        $detectedJdk = Test-JdkCandidate $cand
+        if ($detectedJdk) {
+            Write-LogInfo "Found valid JDK at: $($detectedJdk.Home)"
+            break
+        }
+    }
+}
+
+# If no compatible JDK is found, report error with helpful instructions
+if (-not $detectedJdk) {
+    Write-LogError "No compatible Java Development Kit (JDK 11+) was found on your system."
+    Write-Host @"
+
+j3270 requires a Java Development Kit (JDK) version 11 or higher (LTS 11, 17, or 21).
+Note: A JRE (runtime only) is not sufficient; the compiler (javac) and archiver (jar) are required.
+
+To install JDK 17 on Windows:
+  • Using Windows Package Manager (winget):
+      winget install EclipseAdoptium.Temurin.17.JDK
+
+  • Using Chocolatey:
+      choco install openjdk17
+
+  • Using Scoop:
+      scoop install openjdk17
+
+  • Or download Eclipse Temurin (Adoptium MSI installer):
+      https://adoptium.net
+
+After installing, restart PowerShell and re-run .\setup.ps1
+"@ -ForegroundColor Yellow
+    exit 1
+}
+
+$env:JAVA_HOME = $detectedJdk.Home
+Write-LogSuccess "JDK verified: $($detectedJdk.Version)"
+Write-LogInfo "Java compiler: $($detectedJdk.Javac)"
+Write-LogInfo "JAR packager:  $($detectedJdk.Jar)"
+Write-LogInfo "Java runtime:  $($detectedJdk.Java)"
+Write-LogInfo "JAVA_HOME:     $($detectedJdk.Home)"
+Write-Host ""
+
+# ------------------------------------------------------------------------------
+# 4. Preparation & Clean
+# ------------------------------------------------------------------------------
+$BuildDir = Join-Path $ScriptDir "build"
+$LibBuildDir = Join-Path $BuildDir "lib3270j"
+$AppBuildDir = Join-Path $BuildDir "j3270"
+
+if ($Clean) {
+    Write-LogInfo "Cleaning build directory ($BuildDir)..."
+    Remove-Item -Path $LibBuildDir, $AppBuildDir -Recurse -Force -ErrorAction SilentlyContinue
+    Remove-Item -Path (Join-Path $BuildDir "MANIFEST.MF") -Force -ErrorAction SilentlyContinue
+    Remove-Item -Path (Join-Path $BuildDir "j3270.jar") -Force -ErrorAction SilentlyContinue
+}
+
+$null = New-Item -ItemType Directory -Path $LibBuildDir -Force
+$null = New-Item -ItemType Directory -Path $AppBuildDir -Force
+
+# ------------------------------------------------------------------------------
+# 5. Compile Core Protocol Engine (lib3270j)
+# ------------------------------------------------------------------------------
+Write-LogInfo "Compiling lib3270j core engine..."
+$libSrcDir = Join-Path $ScriptDir "lib3270j\src\main\java"
+$libSources = Get-ChildItem -Path $libSrcDir -Filter *.java -Recurse | Select-Object -ExpandProperty FullName
+
+if (-not $libSources -or $libSources.Count -eq 0) {
+    Write-LogError "No source files found in $libSrcDir"
+    exit 1
+}
+
+$libSourcesFile = Join-Path $BuildDir "lib_sources.txt"
+$libSources | ForEach-Object { "`"$_`"" } | Set-Content -Path $libSourcesFile -Encoding UTF8
+
+& $detectedJdk.Javac -d $LibBuildDir "@$libSourcesFile"
+if ($LASTEXITCODE -ne 0) {
+    Write-LogError "Compilation of lib3270j failed with exit code $LASTEXITCODE."
+    exit $LASTEXITCODE
+}
+Remove-Item -Path $libSourcesFile -Force -ErrorAction SilentlyContinue
+Write-LogSuccess "lib3270j compiled successfully."
+
+# ------------------------------------------------------------------------------
+# 6. Compile Desktop Application (j3270)
+# ------------------------------------------------------------------------------
+Write-LogInfo "Compiling j3270 terminal emulator..."
+$appSrcDir = Join-Path $ScriptDir "j3270\src\main\java"
+$appSources = Get-ChildItem -Path $appSrcDir -Filter *.java -Recurse | Select-Object -ExpandProperty FullName
+
+if (-not $appSources -or $appSources.Count -eq 0) {
+    Write-LogError "No source files found in $appSrcDir"
+    exit 1
+}
+
+$appSourcesFile = Join-Path $BuildDir "app_sources.txt"
+$appSources | ForEach-Object { "`"$_`"" } | Set-Content -Path $appSourcesFile -Encoding UTF8
+
+& $detectedJdk.Javac -cp $LibBuildDir -d $AppBuildDir "@$appSourcesFile"
+if ($LASTEXITCODE -ne 0) {
+    Write-LogError "Compilation of j3270 failed with exit code $LASTEXITCODE."
+    exit $LASTEXITCODE
+}
+Remove-Item -Path $appSourcesFile -Force -ErrorAction SilentlyContinue
+Write-LogSuccess "j3270 application compiled successfully."
+
+# Copy any resources if present
+$appResDir = Join-Path $ScriptDir "j3270\src\main\resources"
+if (Test-Path $appResDir) {
+    Copy-Item -Path (Join-Path $appResDir "*") -Destination $AppBuildDir -Recurse -Force -ErrorAction SilentlyContinue
+}
+$libResDir = Join-Path $ScriptDir "lib3270j\src\main\resources"
+if (Test-Path $libResDir) {
+    Copy-Item -Path (Join-Path $libResDir "*") -Destination $LibBuildDir -Recurse -Force -ErrorAction SilentlyContinue
+}
+
+# ------------------------------------------------------------------------------
+# 7. Package Standalone Executable JAR
+# ------------------------------------------------------------------------------
+Write-LogInfo "Packaging standalone executable JAR..."
+$manifestFile = Join-Path $BuildDir "MANIFEST.MF"
+$manifestText = "Manifest-Version: 1.0`r`nMain-Class: haus.nightmare.j3270.J3270App`r`nImplementation-Title: j3270`r`nImplementation-Version: 0.1.0`r`nCreated-By: j3270 setup.ps1`r`n`r`n"
+[System.IO.File]::WriteAllText($manifestFile, $manifestText)
+
+$jarFile = Join-Path $BuildDir "j3270.jar"
+& $detectedJdk.Jar cvfm $jarFile $manifestFile -C $LibBuildDir . -C $AppBuildDir . | Out-Null
+
+if (-not (Test-Path $jarFile)) {
+    Write-LogError "Failed to create executable JAR at $jarFile"
+    exit 1
+}
+
+$jarItem = Get-Item $jarFile
+$jarSizeKB = [math]::Round($jarItem.Length / 1KB, 1)
+
+Write-Host "`n=== Build Successful ===`n" -ForegroundColor Green
+Write-LogSuccess "Executable JAR created: $jarFile (${jarSizeKB} KB)"
+
+Write-Host @"
+
+To run j3270:
+  java -jar "$jarFile"
+  # Or with arguments:
+  java -jar "$jarFile" mainframe.example.com 23 4
+"@ -ForegroundColor White
+
+# ------------------------------------------------------------------------------
+# 8. Run Tests (if requested)
+# ------------------------------------------------------------------------------
+if ($Test) {
+    Write-Host "`n=== Running Unit Tests ===`n" -ForegroundColor White
+    $testScript = Join-Path $ScriptDir "test_all.sh"
+    if (Test-Path $testScript) {
+        & sh $testScript
+    } else {
+        Write-LogWarn "No test runner script found at $testScript"
+    }
+}
+
+# ------------------------------------------------------------------------------
+# 9. Launch Application (if requested)
+# ------------------------------------------------------------------------------
+if ($Run) {
+    Write-LogInfo "Launching j3270..."
+    if ($isWindows) {
+        Start-Process -FilePath $detectedJdk.Java -ArgumentList (@("-jar", "`"$jarFile`"") + $RunArgs)
+    } else {
+        & $detectedJdk.Java -jar $jarFile @RunArgs
+    }
+}
diff --git a/setup.sh b/setup.sh
new file mode 100755
index 0000000..32e3f9c
--- /dev/null
+++ b/setup.sh
@@ -0,0 +1,428 @@
+#!/bin/sh
+# ==============================================================================
+# j3270 Setup Script (POSIX Shell)
+# Detects Java 11+ JDK and builds j3270 standalone executable JAR.
+#
+# Usage:
+#   ./setup.sh [options] [-- run-arguments]
+#
+# Options:
+#   -r, --run       Launch j3270 immediately after successful build
+#   -t, --test      Run test suite after build
+#   -c, --clean     Clean build directory before compiling
+#   -h, --help      Show this help message
+# ==============================================================================
+set -e
+
+# Resolve directory of this script
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+cd "$SCRIPT_DIR"
+
+# ANSI color codes (if output is to an interactive terminal)
+if [ -t 1 ]; then
+    BOLD="\033[1m"
+    GREEN="\033[1;32m"
+    YELLOW="\033[1;33m"
+    CYAN="\033[1;36m"
+    RED="\033[1;31m"
+    RESET="\033[0m"
+else
+    BOLD=""
+    GREEN=""
+    YELLOW=""
+    CYAN=""
+    RED=""
+    RESET=""
+fi
+
+log_info()    { printf "%b[INFO]%b %s\n" "$CYAN" "$RESET" "$*"; }
+log_success() { printf "%b[OK]%b   %s\n" "$GREEN" "$RESET" "$*"; }
+log_warn()    { printf "%b[WARN]%b %s\n" "$YELLOW" "$RESET" "$*"; }
+log_error()   { printf "%b[ERROR]%b %s\n" "$RED" "$RESET" "$*"; }
+
+show_help() {
+    cat << EOF
+j3270 Terminal Emulator - Setup and Build Script
+
+Usage:
+  ./setup.sh [options] [-- run-arguments]
+
+Options:
+  -r, --run        Build and immediately launch j3270
+  -t, --test       Run automated unit tests after build
+  -c, --clean      Remove previous build artifacts before building
+  -h, --help       Show this help message
+
+Examples:
+  ./setup.sh
+  ./setup.sh --clean
+  ./setup.sh --run
+  ./setup.sh --run -- mainframe.example.com 23 4
+  ./setup.sh --test
+EOF
+}
+
+# Parse command line flags
+DO_RUN=0
+DO_TEST=0
+DO_CLEAN=0
+RUN_ARGS=""
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        -r|--run)
+            DO_RUN=1
+            shift
+            ;;
+        -t|--test)
+            DO_TEST=1
+            shift
+            ;;
+        -c|--clean)
+            DO_CLEAN=1
+            shift
+            ;;
+        -h|--help)
+            show_help
+            exit 0
+            ;;
+        --)
+            shift
+            RUN_ARGS="$*"
+            break
+            ;;
+        *)
+            RUN_ARGS="$*"
+            break
+            ;;
+    esac
+done
+
+printf "\n%b=== j3270 Setup & Build ===%b\n\n" "$BOLD" "$RESET"
+
+# ------------------------------------------------------------------------------
+# 1. Java Version & JDK Toolchain Detection
+# ------------------------------------------------------------------------------
+
+# Extracts the integer major version from a javac or java version string
+# Examples: "javac 11.0.19" -> 11, "javac 17.0.2" -> 17, "javac 1.8.0_292" -> 8
+parse_major_version() {
+    raw_str="$1"
+    ver_token=$(echo "$raw_str" | sed -n \
+        -e 's/.*javac  *\([0-9][0-9._]*\).*/\1/p' \
+        -e 's/.*version  *"\([0-9][0-9._]*\)".*/\1/p' \
+        -e 's/.*version  *\([0-9][0-9._]*\).*/\1/p' | head -n 1)
+
+    if [ -n "$ver_token" ]; then
+        echo "$ver_token" | sed -e 's/^1\.//' -e 's/[^0-9].*//'
+    fi
+}
+
+# Checks if a given directory contains a valid JDK >= 11
+# Sets JAVAC_BIN, JAR_BIN, JAVA_BIN, JAVA_VERSION if valid
+test_jdk_candidate() {
+    cand_home="$1"
+    cand_javac=""
+    cand_jar=""
+    cand_java=""
+
+    if [ -n "$cand_home" ] && [ -d "$cand_home" ]; then
+        if [ -x "$cand_home/bin/javac" ]; then cand_javac="$cand_home/bin/javac"; fi
+        if [ -x "$cand_home/bin/jar" ];   then cand_jar="$cand_home/bin/jar"; fi
+        if [ -x "$cand_home/bin/java" ];  then cand_java="$cand_home/bin/java"; fi
+    fi
+
+    if [ -z "$cand_javac" ] || [ -z "$cand_jar" ] || [ -z "$cand_java" ]; then
+        return 1
+    fi
+
+    # Verify that javac actually executes successfully
+    if ! "$cand_javac" -version >/dev/null 2>&1; then
+        return 1
+    fi
+
+    raw_ver=$("$cand_javac" -version 2>&1)
+    major_num=$(parse_major_version "$raw_ver")
+
+    if [ -n "$major_num" ] && [ "$major_num" -ge 11 ] 2>/dev/null; then
+        JAVAC_BIN="$cand_javac"
+        JAR_BIN="$cand_jar"
+        JAVA_BIN="$cand_java"
+        JAVA_VERSION="$raw_ver"
+        DETECTED_JAVA_HOME="$cand_home"
+        return 0
+    fi
+
+    return 1
+}
+
+JAVAC_BIN=""
+JAR_BIN=""
+JAVA_BIN=""
+JAVA_VERSION=""
+DETECTED_JAVA_HOME=""
+
+log_info "Searching for a compatible Java Development Kit (JDK 11+)..."
+
+# Strategy A: Check user-specified JAVA_HOME
+if [ -n "$JAVA_HOME" ]; then
+    if test_jdk_candidate "$JAVA_HOME"; then
+        log_info "Found valid JDK in \$JAVA_HOME"
+    fi
+fi
+
+# Strategy B: Check current PATH commands (handling potential macOS /usr/bin stubs)
+if [ -z "$JAVAC_BIN" ] && command -v javac >/dev/null 2>&1 && command -v jar >/dev/null 2>&1 && command -v java >/dev/null 2>&1; then
+    if javac -version >/dev/null 2>&1; then
+        raw_ver=$(javac -version 2>&1)
+        major_num=$(parse_major_version "$raw_ver")
+        if [ -n "$major_num" ] && [ "$major_num" -ge 11 ] 2>/dev/null; then
+            JAVAC_BIN="$(command -v javac)"
+            JAR_BIN="$(command -v jar)"
+            JAVA_BIN="$(command -v java)"
+            JAVA_VERSION="$raw_ver"
+            log_info "Found valid JDK on system PATH"
+        fi
+    fi
+fi
+
+# Strategy C: macOS java_home utility
+if [ -z "$JAVAC_BIN" ] && [ -x /usr/libexec/java_home ]; then
+    for v in 11 17 21 24 ""; do
+        if [ -n "$v" ]; then
+            mhome="$(/usr/libexec/java_home -v "$v+" 2>/dev/null || true)"
+        else
+            mhome="$(/usr/libexec/java_home 2>/dev/null || true)"
+        fi
+        if [ -n "$mhome" ] && test_jdk_candidate "$mhome"; then
+            log_info "Found macOS JDK via /usr/libexec/java_home: $mhome"
+            break
+        fi
+    done
+fi
+
+# Strategy D: Check standard package manager & OS installation directories
+if [ -z "$JAVAC_BIN" ]; then
+    candidate_paths="
+        /opt/homebrew/opt/openjdk/libexec/openjdk.jdk/Contents/Home
+        /opt/homebrew/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home
+        /opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home
+        /opt/homebrew/opt/openjdk@11/libexec/openjdk.jdk/Contents/Home
+        /opt/homebrew/opt/openjdk
+        /opt/homebrew/opt/openjdk@21
+        /opt/homebrew/opt/openjdk@17
+        /opt/homebrew/opt/openjdk@11
+        /usr/local/opt/openjdk/libexec/openjdk.jdk/Contents/Home
+        /usr/local/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home
+        /usr/local/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home
+        /usr/local/opt/openjdk@11/libexec/openjdk.jdk/Contents/Home
+        /usr/local/opt/openjdk
+        /Library/Java/JavaVirtualMachines/*/Contents/Home
+        $HOME/Library/Java/JavaVirtualMachines/*/Contents/Home
+        /usr/lib/jvm/default-java
+        /usr/lib/jvm/java-21-openjdk*
+        /usr/lib/jvm/java-17-openjdk*
+        /usr/lib/jvm/java-11-openjdk*
+        /usr/lib/jvm/temurin-21*
+        /usr/lib/jvm/temurin-17*
+        /usr/lib/jvm/temurin-11*
+        /usr/lib/jvm/semeru-21*
+        /usr/lib/jvm/semeru-17*
+        /usr/lib/jvm/semeru-11*
+        /usr/lib/jvm/zulu-21*
+        /usr/lib/jvm/zulu-17*
+        /usr/lib/jvm/zulu-11*
+        /usr/lib/jvm/*
+        /usr/java/*
+        /usr/local/openjdk21
+        /usr/local/openjdk17
+        /usr/local/openjdk11
+        /usr/local/openjdk*
+        $HOME/.sdkman/candidates/java/current
+        $HOME/.sdkman/candidates/java/*
+        $HOME/.asdf/installs/java/*
+        $HOME/.jenv/versions/*
+    "
+
+    for cand in $candidate_paths; do
+        if [ -d "$cand" ] && test_jdk_candidate "$cand"; then
+            log_info "Found compatible JDK at: $cand"
+            break
+        fi
+    done
+fi
+
+# If no compatible JDK is found, provide OS-tailored installation help
+if [ -z "$JAVAC_BIN" ] || [ -z "$JAR_BIN" ] || [ -z "$JAVA_BIN" ]; then
+    log_error "No compatible Java Development Kit (JDK 11+) was found on your system."
+    printf "\n"
+    printf "j3270 requires a Java Development Kit (JDK) version 11 or higher (LTS 11, 17, or 21).\n"
+    printf "Note: A JRE (runtime only) is not sufficient; the compiler (javac) and archiver (jar) are required.\n\n"
+    printf "%bTo install JDK 11+ on your system:%b\n\n" "$BOLD" "$RESET"
+
+    UNAME_S="$(uname -s 2>/dev/null || echo "Unknown")"
+    case "$UNAME_S" in
+        Darwin)
+            printf "  • Using Homebrew:\n"
+            printf "      brew install openjdk@17\n"
+            printf "      sudo ln -sfn /opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk-17.jdk\n\n"
+            printf "  • Or download Eclipse Temurin (Adoptium PKG installer):\n"
+            printf "      https://adoptium.net\n\n"
+            ;;
+        Linux)
+            if command -v apt-get >/dev/null 2>&1; then
+                printf "  • Debian / Ubuntu / Linux Mint:\n"
+                printf "      sudo apt update && sudo apt install -y openjdk-17-jdk\n\n"
+            elif command -v dnf >/dev/null 2>&1; then
+                printf "  • Fedora / RHEL / CentOS / Rocky / AlmaLinux:\n"
+                printf "      sudo dnf install -y java-17-openjdk-devel\n\n"
+            elif command -v pacman >/dev/null 2>&1; then
+                printf "  • Arch Linux / Manjaro:\n"
+                printf "      sudo pacman -S jdk17-openjdk\n\n"
+            elif command -v apk >/dev/null 2>&1; then
+                printf "  • Alpine Linux:\n"
+                printf "      sudo apk add openjdk17\n\n"
+            elif command -v zypper >/dev/null 2>&1; then
+                printf "  • openSUSE:\n"
+                printf "      sudo zypper install -y java-17-openjdk-devel\n\n"
+            else
+                printf "  • Install JDK 17 via your system package manager or SDKMAN:\n"
+                printf "      curl -s \"https://get.sdkman.io\" | bash\n"
+                printf "      sdk install java 17.0.10-tem\n\n"
+            fi
+            ;;
+        FreeBSD|OpenBSD|NetBSD)
+            printf "  • BSD package manager:\n"
+            printf "      pkg install openjdk17\n\n"
+            ;;
+        *)
+            printf "  • Download Eclipse Temurin JDK:\n"
+            printf "      https://adoptium.net\n\n"
+            ;;
+    esac
+
+    printf "After installing, re-run ./setup.sh\n\n"
+    exit 1
+fi
+
+if [ -n "$DETECTED_JAVA_HOME" ]; then
+    export JAVA_HOME="$DETECTED_JAVA_HOME"
+fi
+
+log_success "JDK verified: $JAVA_VERSION"
+log_info "Java compiler: $JAVAC_BIN"
+log_info "JAR packager:  $JAR_BIN"
+log_info "Java runtime:  $JAVA_BIN"
+if [ -n "$JAVA_HOME" ]; then
+    log_info "JAVA_HOME:     $JAVA_HOME"
+fi
+printf "\n"
+
+# ------------------------------------------------------------------------------
+# 2. Preparation & Clean
+# ------------------------------------------------------------------------------
+BUILD_DIR="$SCRIPT_DIR/build"
+
+if [ "$DO_CLEAN" -eq 1 ]; then
+    log_info "Cleaning build directory ($BUILD_DIR)..."
+    rm -rf "$BUILD_DIR/lib3270j" "$BUILD_DIR/j3270" "$BUILD_DIR/MANIFEST.MF" "$BUILD_DIR/j3270.jar"
+fi
+
+mkdir -p "$BUILD_DIR/lib3270j" "$BUILD_DIR/j3270"
+
+# ------------------------------------------------------------------------------
+# 3. Compile Core Protocol Engine (lib3270j)
+# ------------------------------------------------------------------------------
+log_info "Compiling lib3270j core engine..."
+find "$SCRIPT_DIR/lib3270j/src/main/java" -name "*.java" | sed 's/^/"/;s/$/"/' > "$BUILD_DIR/lib_sources.txt"
+
+if [ ! -s "$BUILD_DIR/lib_sources.txt" ]; then
+    log_error "No source files found in lib3270j/src/main/java"
+    exit 1
+fi
+
+"$JAVAC_BIN" -d "$BUILD_DIR/lib3270j" @"$BUILD_DIR/lib_sources.txt"
+rm -f "$BUILD_DIR/lib_sources.txt"
+log_success "lib3270j compiled successfully."
+
+# ------------------------------------------------------------------------------
+# 4. Compile Desktop Application (j3270)
+# ------------------------------------------------------------------------------
+log_info "Compiling j3270 terminal emulator..."
+find "$SCRIPT_DIR/j3270/src/main/java" -name "*.java" | sed 's/^/"/;s/$/"/' > "$BUILD_DIR/app_sources.txt"
+
+if [ ! -s "$BUILD_DIR/app_sources.txt" ]; then
+    log_error "No source files found in j3270/src/main/java"
+    exit 1
+fi
+
+"$JAVAC_BIN" -cp "$BUILD_DIR/lib3270j" -d "$BUILD_DIR/j3270" @"$BUILD_DIR/app_sources.txt"
+rm -f "$BUILD_DIR/app_sources.txt"
+log_success "j3270 application compiled successfully."
+
+# Copy any resources if present
+if [ -d "$SCRIPT_DIR/j3270/src/main/resources" ]; then
+    cp -r "$SCRIPT_DIR/j3270/src/main/resources/"* "$BUILD_DIR/j3270/" 2>/dev/null || true
+fi
+if [ -d "$SCRIPT_DIR/lib3270j/src/main/resources" ]; then
+    cp -r "$SCRIPT_DIR/lib3270j/src/main/resources/"* "$BUILD_DIR/lib3270j/" 2>/dev/null || true
+fi
+
+# ------------------------------------------------------------------------------
+# 5. Package Standalone Executable JAR
+# ------------------------------------------------------------------------------
+log_info "Packaging standalone executable JAR..."
+
+cat << 'EOF' > "$BUILD_DIR/MANIFEST.MF"
+Manifest-Version: 1.0
+Main-Class: haus.nightmare.j3270.J3270App
+Implementation-Title: j3270
+Implementation-Version: 0.1.0
+Created-By: j3270 setup.sh
+
+EOF
+
+"$JAR_BIN" cvfm "$BUILD_DIR/j3270.jar" "$BUILD_DIR/MANIFEST.MF" \
+    -C "$BUILD_DIR/lib3270j" . \
+    -C "$BUILD_DIR/j3270" . > /dev/null
+
+if [ ! -f "$BUILD_DIR/j3270.jar" ]; then
+    log_error "Failed to create $BUILD_DIR/j3270.jar"
+    exit 1
+fi
+
+JAR_SIZE=$(ls -lh "$BUILD_DIR/j3270.jar" | awk '{print $5}')
+printf "\n%b=== Build Successful ===%b\n" "$BOLD" "$RESET"
+log_success "Executable JAR: $BUILD_DIR/j3270.jar ($JAR_SIZE)"
+
+printf "\n%bTo run j3270:%b\n" "$BOLD" "$RESET"
+printf "  ./run.sh\n"
+printf "  # Or directly:\n"
+printf "  %s -jar \"%s/build/j3270.jar\"\n\n" "$JAVA_BIN" "$SCRIPT_DIR"
+
+# ------------------------------------------------------------------------------
+# 6. Run Tests (if requested)
+# ------------------------------------------------------------------------------
+if [ "$DO_TEST" -eq 1 ]; then
+    printf "%b=== Running Unit Tests ===%b\n" "$BOLD" "$RESET"
+    if [ -x "$SCRIPT_DIR/test_all.sh" ]; then
+        sh "$SCRIPT_DIR/test_all.sh"
+    elif [ -x "$SCRIPT_DIR/build_all.sh" ]; then
+        sh "$SCRIPT_DIR/build_all.sh" test
+    fi
+fi
+
+# ------------------------------------------------------------------------------
+# 7. Launch Application (if requested)
+# ------------------------------------------------------------------------------
+if [ "$DO_RUN" -eq 1 ]; then
+    log_info "Launching j3270..."
+    if [ "$(uname -s)" = "Darwin" ]; then
+        # On macOS, enable native application menu bar
+        exec "$JAVA_BIN" -Dapple.laf.useScreenMenuBar=true \
+                         -Dapple.awt.application.name=j3270 \
+                         -jar "$BUILD_DIR/j3270.jar" $RUN_ARGS
+    else
+        exec "$JAVA_BIN" -jar "$BUILD_DIR/j3270.jar" $RUN_ARGS
+    fi
+fi
diff --git a/test_all.sh b/test_all.sh
index 860eab3..9316909 100755
--- a/test_all.sh
+++ b/test_all.sh
@@ -17,15 +17,31 @@ if [ -n "$JAVA_HOME" ] && [ -x "$JAVA_HOME/bin/javac" ] && [ -x "$JAVA_HOME/bin/
     JAVAC_BIN="$JAVA_HOME/bin/javac"
     JAVA_BIN="$JAVA_HOME/bin/java"
 elif command -v javac >/dev/null 2>&1 && command -v java >/dev/null 2>&1; then
-    JAVAC_BIN="$(command -v javac)"
-    JAVA_BIN="$(command -v java)"
-else
-    for h in "$HOME/.sdkman/candidates/java/current" \
+    if javac -version >/dev/null 2>&1; then
+        JAVAC_BIN="$(command -v javac)"
+        JAVA_BIN="$(command -v java)"
+    fi
+fi
+
+if [ -z "$JAVAC_BIN" ] || [ -z "$JAVA_BIN" ]; then
+    if [ -x /usr/libexec/java_home ]; then
+        MAC_JAVA_HOME="$(/usr/libexec/java_home 2>/dev/null || true)"
+        if [ -n "$MAC_JAVA_HOME" ] && [ -x "$MAC_JAVA_HOME/bin/javac" ] && [ -x "$MAC_JAVA_HOME/bin/java" ]; then
+            export JAVA_HOME="$MAC_JAVA_HOME"
+            JAVAC_BIN="$JAVA_HOME/bin/javac"
+            JAVA_BIN="$JAVA_HOME/bin/java"
+        fi
+    fi
+fi
+
+if [ -z "$JAVAC_BIN" ] || [ -z "$JAVA_BIN" ]; then
+    for h in /usr/lib/jvm/default-java \
              /usr/lib/jvm/java-21-openjdk* \
              /usr/lib/jvm/java-17-openjdk* \
              /usr/lib/jvm/java-11-openjdk* \
-             /usr/lib/jvm/default-java \
-             /Library/Java/JavaVirtualMachines/*/Contents/Home; do
+             /Library/Java/JavaVirtualMachines/*/Contents/Home \
+             /opt/homebrew/opt/openjdk/libexec/openjdk.jdk/Contents/Home \
+             /opt/homebrew/opt/openjdk; do
         if [ -d "$h" ] && [ -x "$h/bin/javac" ] && [ -x "$h/bin/java" ]; then
             export JAVA_HOME="$h"
             JAVAC_BIN="$JAVA_HOME/bin/javac"