Adds javadocs for Service Bus (Azure#36844)

* Add javadocs for admin client.

* Add javadocs for builder.

* Adding javadocs for async client.

* Adding javadocs for sync client.

* Adding javadocs for sync client.

* Add additional async javadocs.

* fix spelling of createqueueoptions

* Add samples for Rule actions and filters.

* Add more information to key concepts.

* Regenerate and fix any broken links from rebase.

* Updating models package-info.

* Remove additional quotation.

* Clean-up package-info samples.

* Update sender samples.

* Add builder documentation.

* Add documentation for ReceiverAsyncClient.

* Update receive code snippets and javadoc.

* Update receive snippets to settle messages.

* Clean up send snippets.

* Add notes to package-info

* Fix spelling.

* Regenerate snippets.

Author: conniey

sdk/servicebus/azure-messaging-servicebus/README.md

@@ -121,7 +121,9 @@ ServiceBusReceiverAsyncClient asyncReceiver = new ServiceBusClientBuilder()
     .queueName(queueName)
     .buildAsyncClient();
 
-// Use the receiver and finally close it.
+// When users are done with the receiver, dispose of the receiver.
+// Clients should be long-lived objects as they require resources
+// and time to establish a connection to the service.
 asyncReceiver.close();
 ```
 
@@ -165,6 +167,15 @@ The snippet below creates a synchronous [`ServiceBusSenderClient`][ServiceBusSen
 queue.
 
 ```java com.azure.messaging.servicebus.servicebussenderclient.createMessageBatch
+TokenCredential credential = new DefaultAzureCredentialBuilder().build();
+
+// 'fullyQualifiedNamespace' will look similar to "{your-namespace}.servicebus.windows.net"
+ServiceBusSenderClient sender = new ServiceBusClientBuilder()
+    .credential(fullyQualifiedNamespace, credential)
+    .sender()
+    .queueName(queueName)
+    .buildClient();
+
 List<ServiceBusMessage> messages = Arrays.asList(
     new ServiceBusMessage("test-1"),
     new ServiceBusMessage("test-2"));
@@ -192,7 +203,9 @@ if (batch.getCount() > 0) {
     sender.sendMessages(batch);
 }
 
-// Finally dispose of the sender.
+// Continue using the sender and finally, dispose of the sender.
+// Clients should be long-lived objects as they require resources
+// and time to establish a connection to the service.
 sender.close();
 ```
 
@@ -203,6 +216,7 @@ To receive messages, you will need to create a `ServiceBusProcessorClient` with
 When receiving message with [PeekLock][peek_lock_mode_docs] mode, it tells the broker that the application logic wants to settle (e.g. complete, abandon) received messages explicitly.
 
 ```java com.azure.messaging.servicebus.servicebusprocessorclient#receive-mode-peek-lock-instantiation
+// Function that gets called whenever a message is received.
 Consumer<ServiceBusReceivedMessageContext> processMessage = context -> {
     final ServiceBusReceivedMessage message = context.getMessage();
     // Randomly complete or abandon each message. Ideally, in real-world scenarios, if the business logic
@@ -212,23 +226,30 @@ Consumer<ServiceBusReceivedMessageContext> processMessage = context -> {
     if (success) {
         try {
             context.complete();
-        } catch (Exception completionError) {
-            System.out.printf("Completion of the message %s failed\n", message.getMessageId());
-            completionError.printStackTrace();
+        } catch (RuntimeException error) {
+            System.out.printf("Completion of the message %s failed.%n Error: %s%n",
+                message.getMessageId(), error);
         }
     } else {
         try {
             context.abandon();
-        } catch (Exception abandonError) {
-            System.out.printf("Abandoning of the message %s failed\n", message.getMessageId());
-            abandonError.printStackTrace();
+        } catch (RuntimeException error) {
+            System.out.printf("Abandoning of the message %s failed.%nError: %s%n",
+                message.getMessageId(), error);
         }
     }
 };
 
 // Sample code that gets called if there's an error
 Consumer<ServiceBusErrorContext> processError = errorContext -> {
-    System.err.println("Error occurred while receiving message: " + errorContext.getException());
+    if (errorContext.getException() instanceof ServiceBusException) {
+        ServiceBusException exception = (ServiceBusException) errorContext.getException();
+
+        System.out.printf("Error source: %s, reason %s%n", errorContext.getErrorSource(),
+            exception.getReason());
+    } else {
+        System.out.printf("Error occurred: %s%n", errorContext.getException());
+    }
 };
 
 TokenCredential tokenCredential = new DefaultAzureCredentialBuilder().build();
@@ -257,6 +278,7 @@ processorClient.close();
 When receiving message with [ReceiveAndDelete][receive_and_delete_mode_docs] mode, tells the broker to consider all messages it sends to the receiving client as settled when sent.
 
 ```java com.azure.messaging.servicebus.servicebusprocessorclient#receive-mode-receive-and-delete-instantiation
+// Function that gets called whenever a message is received.
 Consumer<ServiceBusReceivedMessageContext> processMessage = context -> {
     final ServiceBusReceivedMessage message = context.getMessage();
     System.out.printf("Processing message. Session: %s, Sequence #: %s. Contents: %s%n",
@@ -265,13 +287,21 @@ Consumer<ServiceBusReceivedMessageContext> processMessage = context -> {
 
 // Sample code that gets called if there's an error
 Consumer<ServiceBusErrorContext> processError = errorContext -> {
-    System.err.println("Error occurred while receiving message: " + errorContext.getException());
+    if (errorContext.getException() instanceof ServiceBusException) {
+        ServiceBusException exception = (ServiceBusException) errorContext.getException();
+
+        System.out.printf("Error source: %s, reason %s%n", errorContext.getErrorSource(),
+            exception.getReason());
+    } else {
+        System.out.printf("Error occurred: %s%n", errorContext.getException());
+    }
 };
 
 TokenCredential tokenCredential = new DefaultAzureCredentialBuilder().build();
 
 // Create the processor client via the builder and its sub-builder
 // 'fullyQualifiedNamespace' will look similar to "{your-namespace}.servicebus.windows.net"
+// 'disableAutoComplete()' will opt in to manual settlement (e.g. complete, abandon).
 ServiceBusProcessorClient processorClient = new ServiceBusClientBuilder()
     .credential(fullyQualifiedNamespace, tokenCredential)
     .processor()
@@ -282,7 +312,6 @@ ServiceBusProcessorClient processorClient = new ServiceBusClientBuilder()
     .disableAutoComplete()
     .buildProcessorClient();
 
-
 // Starts the processor in the background. Control returns immediately.
 processorClient.start();
 
@@ -364,7 +393,9 @@ ServiceBusReceiverClient receiver = new ServiceBusClientBuilder()
     .subQueue(SubQueue.DEAD_LETTER_QUEUE)
     .buildClient();
 
-// Use the receiver and finally close it.
+// When users are done with the receiver, dispose of the receiver.
+// Clients should be long-lived objects as they require resources
+// and time to establish a connection to the service.
 receiver.close();
 ```
 
@@ -375,14 +406,15 @@ between clients which can be achieved by sharing the top level builder as shown
 ```java com.azure.messaging.servicebus.connection.sharing
 TokenCredential credential = new DefaultAzureCredentialBuilder().build();
 
-// Retrieve 'connectionString' and 'queueName' from your configuration.
 // 'fullyQualifiedNamespace' will look similar to "{your-namespace}.servicebus.windows.net"
+// Any clients created from this builder will share the underlying connection.
 ServiceBusClientBuilder sharedConnectionBuilder = new ServiceBusClientBuilder()
     .credential(fullyQualifiedNamespace, credential);
 
 // Create receiver and sender which will share the connection.
 ServiceBusReceiverClient receiver = sharedConnectionBuilder
     .receiver()
+    .receiveMode(ServiceBusReceiveMode.PEEK_LOCK)
     .queueName(queueName)
     .buildClient();
 ServiceBusSenderClient sender = sharedConnectionBuilder
@@ -395,6 +427,8 @@ try {
     sender.sendMessage(new ServiceBusMessage("payload"));
     receiver.receiveMessages(1);
 } finally {
+    // Clients should be long-lived objects as they require resources
+    // and time to establish a connection to the service.
     sender.close();
     receiver.close();
 }