diff --git a/javaTest/pom.xml b/javaTest/pom.xml
new file mode 100644
index 0000000..9385f63
--- /dev/null
+++ b/javaTest/pom.xml
@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.ft546.wcs</groupId>
+    <artifactId>wcs-dispatch-traffic-demo</artifactId>
+    <version>1.0.0-SNAPSHOT</version>
+    <name>FT546 WCS Dispatch and Traffic Demo</name>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <junit.version>5.10.2</junit.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <release>8</release>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.2.5</version>
+            </plugin>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.1.0</version>
+                <configuration>
+                    <mainClass>com.ft546.wcs.demo.DemoApplication</mainClass>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/javaTest/src/main/java/com/ft546/wcs/demo/model/DispatchQueueEntry.java b/javaTest/src/main/java/com/ft546/wcs/demo/model/DispatchQueueEntry.java
new file mode 100644
index 0000000..917fb35
--- /dev/null
+++ b/javaTest/src/main/java/com/ft546/wcs/demo/model/DispatchQueueEntry.java
@@ -0,0 +1,125 @@
+package com.ft546.wcs.demo.model;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public final class DispatchQueueEntry {
+    public enum QueueType {
+        BUSINESS,
+        AVOIDANCE
+    }
+
+    private final String queueId;
+    private final String taskId;
+    private final String vehicleId;
+    private final QueueType queueType;
+    private final String startSite;
+    private final String endSite;
+    private final int priority;
+    private int issued;
+    private int executionStatus;
+    private List<String> path;
+
+    private DispatchQueueEntry(
+        String queueId,
+        String taskId,
+        String vehicleId,
+        QueueType queueType,
+        String startSite,
+        String endSite,
+        int priority
+    ) {
+        this.queueId = queueId;
+        this.taskId = taskId;
+        this.vehicleId = vehicleId;
+        this.queueType = queueType;
+        this.startSite = startSite;
+        this.endSite = endSite;
+        this.priority = priority;
+        this.issued = 0;
+        this.executionStatus = 1;
+        this.path = Collections.emptyList();
+    }
+
+    public static DispatchQueueEntry business(DispatchTask task, String vehicleId) {
+        if (task == null) {
+            throw new IllegalArgumentException("task must not be null");
+        }
+        if (vehicleId == null || vehicleId.trim().isEmpty()) {
+            throw new IllegalArgumentException("vehicle id must not be blank");
+        }
+        return new DispatchQueueEntry(
+            task.getTaskId(),
+            task.getTaskId(),
+            vehicleId,
+            QueueType.BUSINESS,
+            task.getSourceSite(),
+            task.getTargetSite(),
+            task.getPriority()
+        );
+    }
+
+    public void markIssued(List<String> issuedPath) {
+        if (issued != 0) {
+            throw new IllegalStateException("queue has already been issued");
+        }
+        if (issuedPath == null || issuedPath.isEmpty()) {
+            throw new IllegalArgumentException("issued path must not be empty");
+        }
+        this.path = Collections.unmodifiableList(new ArrayList<String>(issuedPath));
+        this.issued = 1;
+        this.executionStatus = 3;
+    }
+
+    public void markCompleted() {
+        if (issued == 0) {
+            throw new IllegalStateException("unissued queue cannot complete");
+        }
+        this.executionStatus = 4;
+    }
+
+    public String getQueueId() {
+        return queueId;
+    }
+
+    public String getTaskId() {
+        return taskId;
+    }
+
+    public String getVehicleId() {
+        return vehicleId;
+    }
+
+    public QueueType getQueueType() {
+        return queueType;
+    }
+
+    public String getStartSite() {
+        return startSite;
+    }
+
+    public String getEndSite() {
+        return endSite;
+    }
+
+    public int getPriority() {
+        return priority;
+    }
+
+    public int getIssued() {
+        return issued;
+    }
+
+    public int getExecutionStatus() {
+        return executionStatus;
+    }
+
+    public boolean isIssued() {
+        return issued == 1;
+    }
+
+    public List<String> getPath() {
+        return path;
+    }
+}
diff --git a/javaTest/src/main/java/com/ft546/wcs/demo/model/DispatchTask.java b/javaTest/src/main/java/com/ft546/wcs/demo/model/DispatchTask.java
new file mode 100644
index 0000000..961a874
--- /dev/null
+++ b/javaTest/src/main/java/com/ft546/wcs/demo/model/DispatchTask.java
@@ -0,0 +1,69 @@
+package com.ft546.wcs.demo.model;
+
+public final class DispatchTask {
+    public enum TaskType {
+        INBOUND,
+        OUTBOUND,
+        RELOCATION
+    }
+
+    private final String taskId;
+    private final TaskType type;
+    private final String sourceSite;
+    private final String targetSite;
+    private final int floor;
+    private final int priority;
+
+    public DispatchTask(
+        String taskId,
+        TaskType type,
+        String sourceSite,
+        String targetSite,
+        int floor,
+        int priority
+    ) {
+        this.taskId = requireText(taskId, "task id");
+        if (type == null) {
+            throw new IllegalArgumentException("task type must not be null");
+        }
+        this.type = type;
+        this.sourceSite = requireText(sourceSite, "source site");
+        this.targetSite = requireText(targetSite, "target site");
+        if (floor <= 0) {
+            throw new IllegalArgumentException("floor must be positive");
+        }
+        this.floor = floor;
+        this.priority = priority;
+    }
+
+    public String getTaskId() {
+        return taskId;
+    }
+
+    public TaskType getType() {
+        return type;
+    }
+
+    public String getSourceSite() {
+        return sourceSite;
+    }
+
+    public String getTargetSite() {
+        return targetSite;
+    }
+
+    public int getFloor() {
+        return floor;
+    }
+
+    public int getPriority() {
+        return priority;
+    }
+
+    private static String requireText(String value, String name) {
+        if (value == null || value.trim().isEmpty()) {
+            throw new IllegalArgumentException(name + " must not be blank");
+        }
+        return value;
+    }
+}
diff --git a/javaTest/src/main/java/com/ft546/wcs/demo/model/Site.java b/javaTest/src/main/java/com/ft546/wcs/demo/model/Site.java
new file mode 100644
index 0000000..ac6e060
--- /dev/null
+++ b/javaTest/src/main/java/com/ft546/wcs/demo/model/Site.java
@@ -0,0 +1,66 @@
+package com.ft546.wcs.demo.model;
+
+import java.util.Objects;
+
+public final class Site {
+    private final String id;
+    private final int floor;
+    private final int x;
+    private final int y;
+    private final String channel;
+
+    public Site(String id, int floor, int x, int y, String channel) {
+        this.id = requireText(id, "site id");
+        if (floor <= 0) {
+            throw new IllegalArgumentException("floor must be positive");
+        }
+        this.floor = floor;
+        this.x = x;
+        this.y = y;
+        this.channel = requireText(channel, "channel");
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public int getFloor() {
+        return floor;
+    }
+
+    public int getX() {
+        return x;
+    }
+
+    public int getY() {
+        return y;
+    }
+
+    public String getChannel() {
+        return channel;
+    }
+
+    private static String requireText(String value, String name) {
+        if (value == null || value.trim().isEmpty()) {
+            throw new IllegalArgumentException(name + " must not be blank");
+        }
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (this == other) {
+            return true;
+        }
+        if (!(other instanceof Site)) {
+            return false;
+        }
+        Site site = (Site) other;
+        return id.equals(site.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+}
diff --git a/javaTest/src/main/java/com/ft546/wcs/demo/model/VehicleSnapshot.java b/javaTest/src/main/java/com/ft546/wcs/demo/model/VehicleSnapshot.java
new file mode 100644
index 0000000..af7960c
--- /dev/null
+++ b/javaTest/src/main/java/com/ft546/wcs/demo/model/VehicleSnapshot.java
@@ -0,0 +1,98 @@
+package com.ft546.wcs.demo.model;
+
+public final class VehicleSnapshot {
+    private final String vehicleId;
+    private final int floor;
+    private final String currentSite;
+    private final int workMode;
+    private final int status;
+    private final int battery;
+    private final boolean connected;
+    private final boolean allowSend;
+    private final boolean cargo;
+
+    public VehicleSnapshot(
+        String vehicleId,
+        int floor,
+        String currentSite,
+        int workMode,
+        int status,
+        int battery,
+        boolean connected,
+        boolean allowSend,
+        boolean cargo
+    ) {
+        this.vehicleId = requireText(vehicleId, "vehicle id");
+        if (floor <= 0) {
+            throw new IllegalArgumentException("floor must be positive");
+        }
+        this.floor = floor;
+        this.currentSite = requireText(currentSite, "current site");
+        this.workMode = workMode;
+        this.status = status;
+        if (battery < 0 || battery > 100) {
+            throw new IllegalArgumentException("battery must be between 0 and 100");
+        }
+        this.battery = battery;
+        this.connected = connected;
+        this.allowSend = allowSend;
+        this.cargo = cargo;
+    }
+
+    public String getVehicleId() {
+        return vehicleId;
+    }
+
+    public int getFloor() {
+        return floor;
+    }
+
+    public String getCurrentSite() {
+        return currentSite;
+    }
+
+    public int getWorkMode() {
+        return workMode;
+    }
+
+    public int getStatus() {
+        return status;
+    }
+
+    public int getBattery() {
+        return battery;
+    }
+
+    public boolean isConnected() {
+        return connected;
+    }
+
+    public boolean isAllowSend() {
+        return allowSend;
+    }
+
+    public boolean isCargo() {
+        return cargo;
+    }
+
+    public VehicleSnapshot at(String siteId, int newFloor) {
+        return new VehicleSnapshot(
+            vehicleId,
+            newFloor,
+            siteId,
+            workMode,
+            status,
+            battery,
+            connected,
+            allowSend,
+            cargo
+        );
+    }
+
+    private static String requireText(String value, String name) {
+        if (value == null || value.trim().isEmpty()) {
+            throw new IllegalArgumentException(name + " must not be blank");
+        }
+        return value;
+    }
+}
diff --git a/javaTest/src/test/java/com/ft546/wcs/demo/QueueLifecycleTest.java b/javaTest/src/test/java/com/ft546/wcs/demo/QueueLifecycleTest.java
new file mode 100644
index 0000000..53285f0
--- /dev/null
+++ b/javaTest/src/test/java/com/ft546/wcs/demo/QueueLifecycleTest.java
@@ -0,0 +1,80 @@
+package com.ft546.wcs.demo;
+
+import com.ft546.wcs.demo.model.DispatchQueueEntry;
+import com.ft546.wcs.demo.model.DispatchTask;
+import com.ft546.wcs.demo.model.Site;
+import com.ft546.wcs.demo.model.VehicleSnapshot;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class QueueLifecycleTest {
+
+    @Test
+    void queueUsesLegacyLifecycleCodes() {
+        DispatchTask task = new DispatchTask(
+            "T-1",
+            DispatchTask.TaskType.OUTBOUND,
+            "A",
+            "B",
+            1,
+            2
+        );
+        DispatchQueueEntry queue = DispatchQueueEntry.business(task, "1");
+
+        assertEquals(0, queue.getIssued());
+        assertEquals(1, queue.getExecutionStatus());
+
+        queue.markIssued(Arrays.asList("A", "B"));
+
+        assertEquals(1, queue.getIssued());
+        assertEquals(3, queue.getExecutionStatus());
+
+        queue.markCompleted();
+
+        assertEquals(4, queue.getExecutionStatus());
+    }
+
+    @Test
+    void queueCopiesPathAndRejectsCompletionBeforeIssue() {
+        DispatchTask task = new DispatchTask(
+            "T-2",
+            DispatchTask.TaskType.INBOUND,
+            "A",
+            "B",
+            1,
+            2
+        );
+        DispatchQueueEntry queue = DispatchQueueEntry.business(task, "1");
+        List<String> path = new java.util.ArrayList<String>(Arrays.asList("A", "B"));
+
+        assertThrows(IllegalStateException.class, queue::markCompleted);
+
+        queue.markIssued(path);
+        path.add("C");
+
+        assertEquals(Arrays.asList("A", "B"), queue.getPath());
+        assertThrows(UnsupportedOperationException.class, () -> queue.getPath().add("D"));
+    }
+
+    @Test
+    void domainInputsRejectInvalidValues() {
+        assertThrows(IllegalArgumentException.class,
+            () -> new Site("", 1, 0, 0, "C1"));
+        assertThrows(IllegalArgumentException.class,
+            () -> new VehicleSnapshot("1", 1, "A", 5, 1, 101, true, true, false));
+        assertThrows(IllegalArgumentException.class,
+            () -> new DispatchTask("", DispatchTask.TaskType.OUTBOUND, "A", "B", 1, 2));
+
+        VehicleSnapshot snapshot = new VehicleSnapshot(
+            "1", 1, "A", 5, 1, 80, true, true, false
+        );
+        assertTrue(snapshot.isConnected());
+        assertEquals("1", snapshot.getVehicleId());
+    }
+}