Device sample updates (#1035)

* Adds exponential backoff to MQTT

* Updates to v1 base URI and ensures TLSv1.2 is used.

Author: gguuss

iot/api-client/manager/src/main/java/com/example/cloud/iot/examples/HttpExampleOptions.java

@@ -33,8 +33,8 @@ public class HttpExampleOptions {
   String cloudRegion = "us-central1";
   int numMessages = 100;
   int tokenExpMins = 20;
-  String httpBridgeAddress = "https://cloudiot-device.googleapis.com";
-  String apiVersion = "v1beta1";
+  String httpBridgeAddress = "https://cloudiotdevice.googleapis.com";
+  String apiVersion = "v1";
   String messageType = "event";
 
   /** Construct an HttpExampleOptions class from command line flags. */

iot/api-client/manager/src/main/java/com/example/cloud/iot/examples/MqttExample.java

@@ -24,6 +24,8 @@
 import java.nio.file.Paths;
 import java.security.KeyFactory;
 import java.security.spec.PKCS8EncodedKeySpec;
+import java.util.Properties;
+
 import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
 import org.eclipse.paho.client.mqttv3.MqttCallback;
 import org.eclipse.paho.client.mqttv3.MqttClient;
@@ -158,6 +160,10 @@ public static void main(String[] args) throws Exception {
     // connection to your device.
     connectOptions.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1_1);
 
+    Properties sslProps = new Properties();
+    sslProps.setProperty("com.ibm.ssl.protocol", "TLSv1.2");
+    connectOptions.setSSLProperties(sslProps);
+
     // With Google Cloud IoT Core, the username field is ignored, however it must be set for the
     // Paho client library to send the password field. The password field is used to transmit a JWT
     // to authorize the device.