Initialize the userMetaData field for iot SDK with the default value (#803)

* Initialize the userMetaData field for iot SDK with default value

Author: desokroshan

aws-android-sdk-iot/src/main/java/com/amazonaws/mobileconnectors/iot/AWSIotMqttManager.java

@@ -162,18 +162,16 @@ public class AWSIotMqttManager {
      */
     private boolean metricsIsEnabled = true;
 
-    /** User metadata string. */
-    String userMetaData;
-
     /**
-     * This is your custom endpoint that allows you to connect to AWS IoT.
+     * User metadata string. getVersion method returns the SDK version that will be sent in
+     * the mqtt connect message if metrics collection is enabled.
      */
-    private final String endpoint;
+    String userMetaData = "?SDK=Android&Version=" + VersionInfoUtils.getVersion();
 
     /**
-     * The SDK version that will be sent in the mqtt connect message if metrics collection is enabled.
+     * This is your custom endpoint that allows you to connect to AWS IoT.
      */
-    private static final String SDK_VERSION = VersionInfoUtils.getVersion();
+    private final String endpoint;
 
     /**
      * Turning on/off metrics collection. By default metrics collection is enabled.
@@ -219,7 +217,7 @@ public boolean isMetricsEnabled() {
      * @param userMetaDataMap userMetaData map
      */
     public void addUserMetaData(Map<String, String> userMetaDataMap) {
-        StringBuilder userMetadata = new StringBuilder("?SDK=Android&Version=" + SDK_VERSION);
+        StringBuilder userMetadata = new StringBuilder(this.userMetaData);
         int baseLength = userMetadata.length();
 
         if (userMetaDataMap != null) {

aws-android-sdk-iot/src/test/java/com/amazonaws/mobileconnectors/iot/AWSIotMqttManagerTest.java

@@ -13,6 +13,7 @@
 import com.amazonaws.regions.Region;
 import com.amazonaws.regions.Regions;
 import com.amazonaws.util.StringUtils;
+import com.amazonaws.util.VersionInfoUtils;
 
 import org.eclipse.paho.client.mqttv3.MqttException;
 import org.eclipse.paho.client.mqttv3.MqttMessage;
@@ -90,6 +91,8 @@ public void testCreateClientWithPrefix() throws Exception {
         AWSIotMqttManager testClient = new AWSIotMqttManager("test-client",
                 Region.getRegion(Regions.US_EAST_1), TEST_ENDPOINT_PREFIX);
 
+        // UserMetaData field before setting additional metadata
+        assertEquals(testClient.userMetaData, "?SDK=Android&Version=" + VersionInfoUtils.getVersion());
         // Set user metadata
         Map<String, String> userMetaData = new HashMap<String, String>();
         userMetaData.put("AFRSDK", "Android");
@@ -108,7 +111,8 @@ public void testCreateClientWithPrefix() throws Exception {
         assertEquals(100L, (long)testClient.getOfflinePublishQueueBound());
         assertEquals(TEST_ENDPOINT_PREFIX, testClient.getAccountEndpointPrefix());
         assertEquals(MqttManagerConnectionState.Disconnected, testClient.getConnectionState());
-        assertNotNull(testClient.userMetaData);
+        assertEquals(testClient.userMetaData, "?SDK=Android&Version=" + VersionInfoUtils.getVersion() +
+                "&AFRSDK=Android&AFRSDKVersion=1.0.0&AFRLibVersion=1.4.1");
 
 
         testClient.setAutoReconnect(false);