diff --git a/pom.xml b/pom.xml
index a0bca46..24216b8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -620,6 +620,12 @@
       <version>17.0</version>
     </dependency>
     <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava-testlib</artifactId>
+      <version>17.0</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
       <groupId>commons-configuration</groupId>
       <artifactId>commons-configuration</artifactId>
       <version>1.10</version>
diff --git a/src/main/java/net/onrc/onos/api/flowmanager/FlowId.java b/src/main/java/net/onrc/onos/api/flowmanager/FlowId.java
index b6bb9f0..3e94c7b 100644
--- a/src/main/java/net/onrc/onos/api/flowmanager/FlowId.java
+++ b/src/main/java/net/onrc/onos/api/flowmanager/FlowId.java
@@ -2,20 +2,25 @@
 
 import java.util.Objects;
 
+import javax.annotation.concurrent.Immutable;
+
 import net.onrc.onos.api.batchoperation.BatchOperationTarget;
 
 /**
  * Represents ID for Flow objects.
+ * <p>
+ * This class is immutable.
  */
-public class FlowId implements BatchOperationTarget {
-    private final long value;
+@Immutable
+public final class FlowId implements BatchOperationTarget {
+    private final long id;
 
     /**
      * Default constructor for Kryo deserialization.
      */
     @Deprecated
     protected FlowId() {
-        value = 0;
+        id = 0;
     }
 
     /**
@@ -26,24 +31,24 @@
      * @param id String representation of the ID.
      */
     public FlowId(long id) {
-        value = id;
+        this.id = id;
     }
 
     @Override
     public String toString() {
-        return Long.toString(value);
+        return "0x" + Long.toHexString(id);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hashCode(value);
+        return Objects.hashCode(id);
     }
 
     @Override
     public boolean equals(Object obj) {
         if (obj instanceof FlowId) {
             FlowId that = (FlowId) obj;
-            return Objects.equals(this.value, that.value);
+            return Objects.equals(this.id, that.id);
         }
         return false;
     }
diff --git a/src/test/java/net/onrc/onos/api/flowmanager/FlowIdTest.java b/src/test/java/net/onrc/onos/api/flowmanager/FlowIdTest.java
index 49981b0..20ffcc0 100644
--- a/src/test/java/net/onrc/onos/api/flowmanager/FlowIdTest.java
+++ b/src/test/java/net/onrc/onos/api/flowmanager/FlowIdTest.java
@@ -1,40 +1,68 @@
 package net.onrc.onos.api.flowmanager;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static net.onrc.onos.core.util.ImmutableClassChecker.assertThatClassIsImmutable;
+import static org.junit.Assert.assertEquals;
+import net.onrc.onos.core.util.TestUtils;
 
+import org.junit.Before;
 import org.junit.Test;
 
+import com.google.common.testing.EqualsTester;
+
+/**
+ * Unit tests for {@link FlowId} class.
+ */
 public class FlowIdTest {
+    private FlowId flowId1;
+    private FlowId flowId2;
+    private FlowId flowId3;
+    private FlowId flowId4;
+    private FlowId flowId5;
 
-    /**
-     * Tests FlowId's equals method.
-     */
-    @Test
-    public void testEquals() {
-        FlowId flow1 = new FlowId(0L);
-        FlowId flow2 = new FlowId(1L);
-        FlowId flow3 = new FlowId(2L);
-        FlowId flow4 = new FlowId(1L);
-
-        assertTrue(flow1.equals(flow1));
-        assertTrue(flow2.equals(flow2));
-        assertTrue(flow3.equals(flow3));
-        assertTrue(flow4.equals(flow4));
-
-        assertFalse(flow1.equals(flow2));
-        assertFalse(flow1.equals(flow3));
-        assertFalse(flow1.equals(flow4));
-        assertFalse(flow2.equals(flow1));
-        assertFalse(flow2.equals(flow3));
-        assertFalse(flow3.equals(flow1));
-        assertFalse(flow3.equals(flow2));
-        assertFalse(flow3.equals(flow4));
-        assertFalse(flow4.equals(flow1));
-        assertFalse(flow4.equals(flow3));
-
-        assertTrue(flow2.equals(flow4));
-        assertTrue(flow4.equals(flow2));
+    @Before
+    public void setUp() {
+        flowId1 = new FlowId(0L);
+        flowId2 = new FlowId(1L);
+        flowId3 = new FlowId(2L);
+        flowId4 = new FlowId(1L);
+        flowId5 = new FlowId(0xABCDEFL);
     }
 
+    /**
+     * Tests {@link FlowId#FlowId(long)} constructor.
+     */
+    @Test
+    public void testConstructor() {
+        assertEquals(0xABCDEFL, TestUtils.getField(flowId5, "id"));
+    }
+
+    /**
+     * Tests the equality of {@link FlowId} objects.
+     */
+    @Test
+    public void testEqualsAndHashCode() {
+        new EqualsTester()
+                .addEqualityGroup(flowId1)
+                .addEqualityGroup(flowId2, flowId4)
+                .addEqualityGroup(flowId3)
+                .addEqualityGroup(flowId5)
+                .testEquals();
+    }
+
+    /**
+     * Tests {@link FlowId#toString()} method.
+     */
+    @Test
+    public void testToString() {
+        assertEquals("0x0", flowId1.toString());
+        assertEquals("0xabcdef", flowId5.toString());
+    }
+
+    /**
+     * Tests if {@link FlowId} is immutable.
+     */
+    @Test
+    public void testImmutable() {
+        assertThatClassIsImmutable(FlowId.class);
+    }
 }