diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php
index 10bc52e..e288f27 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php
@@ -62,9 +62,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $id = $this->getPluginId();
     if ($category = db_query('SELECT cid, title, block FROM {aggregator_category} WHERE cid = :cid', array(':cid' => $id))->fetchObject()) {
       $result = db_query_range('SELECT i.* FROM {aggregator_category_item} ci LEFT JOIN {aggregator_item} i ON ci.iid = i.iid WHERE ci.cid = :cid ORDER BY i.timestamp DESC, i.iid DESC', 0, $this->configuration['block_count'], array(':cid' => $category->cid));
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php
index afcef0e..f522b8f 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php
@@ -62,9 +62,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     // Plugin IDs look something like this: aggregator_feed_block:1.
     list(, $id) = explode(':', $this->getPluginId());
     if ($feed = db_query('SELECT fid, title, block FROM {aggregator_feed} WHERE block <> 0 AND fid = :fid', array(':fid' => $id))->fetchObject()) {
diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 18b9d27..febb1bf 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -326,8 +326,10 @@ function _block_get_renderable_region($list = array()) {
     else {
       $key_components = explode('.', $key);
       $id = array_pop($key_components);
+      // @todo http://drupal.org/node/1942286
       $build[$key] = array(
-        '#block' => $block,
+        '#entity' => $block,
+        '#block' => (object) $block->getPlugin()->getConfig(),
         '#weight' => $block->get('weight'),
         '#theme_wrappers' => array('block'),
         '#pre_render' => array('_block_get_renderable_block'),
@@ -488,11 +490,12 @@ function block_load($entity_id) {
  *   A renderable array.
  */
 function _block_get_renderable_block($element) {
-  $block = $element['#block'];
+  $block = $element['#entity'];
   // Don't bother to build blocks that aren't accessible.
   if ($element['#access'] = $block->access()) {
     $element += entity_view($block, 'block');
   }
+  unset($element['#entity']);
   return $element;
 }
 
@@ -534,7 +537,8 @@ function block_rebuild() {
 function template_preprocess_block(&$variables) {
   $block_counter = &drupal_static(__FUNCTION__, array());
 
-  $variables['block'] = (object) $variables['elements']['#block_config'];
+  // @todo http://drupal.org/node/1942286
+  $variables['block'] = (object) $variables['elements']['#block'];
 
   // All blocks get an independent counter for each region.
   if (!isset($block_counter[$variables['block']->region])) {
@@ -565,13 +569,13 @@ function template_preprocess_block(&$variables) {
 
   // We can safely explode on : because we know the Block plugin type manager
   // enforces that delimiter for all derivatives.
-  $parts = explode(':', $variables['elements']['#block']->get('plugin'));
+  $parts = explode(':', $variables['elements']['#block']->plugin);
   $suggestion = 'block';
   while ($part = array_shift($parts)) {
     $variables['theme_hook_suggestions'][] = $suggestion .= '__' . strtr($part, '-', '_');
   }
   // Create a valid HTML ID and make sure it is unique.
-  if ($id = $variables['elements']['#block']->id()) {
+  if ($id = $variables['elements']['#block']->id) {
     $config_id = explode('.', $id);
     $machine_name = array_pop($config_id);
     $variables['block_html_id'] = drupal_html_id('block-' . $machine_name);
diff --git a/core/modules/block/custom_block/custom_block.module b/core/modules/block/custom_block/custom_block.module
index a3ce18c..ec678d8 100644
--- a/core/modules/block/custom_block/custom_block.module
+++ b/core/modules/block/custom_block/custom_block.module
@@ -8,7 +8,7 @@
 use Drupal\custom_block\Plugin\Core\Entity\CustomBlockType;
 use Drupal\custom_block\Plugin\Core\Entity\CustomBlock;
 use Drupal\custom_block\Plugin\block\block\CustomBlockBlock;
-use Drupal\block\Plugin\Core\Entity\Block;
+use Drupal\block\BlockInterface;
 
 /**
  * Implements hook_menu_local_tasks().
@@ -292,9 +292,9 @@ function custom_block_admin_paths() {
 /**
  * Implements hook_block_view_alter().
  */
-function custom_block_block_view_alter(array &$build, Block $block) {
+function custom_block_block_view_alter(array &$build, BlockInterface $block) {
   // Add contextual links for custom blocks.
-  if ($block->getPlugin() instanceof CustomBlockBlock) {
+  if ($block instanceof CustomBlockBlock) {
     // Move contextual links from inner content to outer wrapper.
     $build['#contextual_links']['custom_block'] = $build['content']['#contextual_links']['custom_block'];
     unset($build['content']['#contextual_links']['custom_block']);
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlockBlock.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlockBlock.php
index 9219264..c0d0e4b 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlockBlock.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlockBlock.php
@@ -73,9 +73,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     // @todo Clean up when http://drupal.org/node/1874498 lands.
     list(, $uuid) = explode(':', $this->getPluginId());
     if ($block = entity_load_by_uuid('custom_block', $uuid)) {
diff --git a/core/modules/block/lib/Drupal/block/BlockBase.php b/core/modules/block/lib/Drupal/block/BlockBase.php
index 9c90a5a..9f83308 100644
--- a/core/modules/block/lib/Drupal/block/BlockBase.php
+++ b/core/modules/block/lib/Drupal/block/BlockBase.php
@@ -9,7 +9,6 @@
 
 use Drupal\Component\Plugin\PluginBase;
 use Drupal\block\Plugin\Core\Entity\Block;
-use Drupal\Component\Plugin\Discovery\DiscoveryInterface;
 
 /**
  * Defines a base block implementation that most blocks plugins will extend.
@@ -21,22 +20,6 @@
 abstract class BlockBase extends PluginBase implements BlockInterface {
 
   /**
-   * The entity using this plugin.
-   *
-   * @var \Drupal\block\Plugin\Core\Entity\Block
-   */
-  protected $entity;
-
-  /**
-   * Overrides \Drupal\Component\Plugin\PluginBase::__construct().
-   */
-  public function __construct(array $configuration, $plugin_id, DiscoveryInterface $discovery, Block $entity) {
-    parent::__construct($configuration, $plugin_id, $discovery);
-
-    $this->entity = $entity;
-  }
-
-  /**
    * Returns plugin-specific settings for the block.
    *
    * Block plugins only need to override this method if they override the
@@ -142,7 +125,7 @@ public function access() {
     global $user;
 
     // Deny access to disabled blocks.
-    if (!$this->entity->get('status')) {
+    if (!$this->configuration['status']) {
       return FALSE;
     }
 
@@ -150,7 +133,7 @@ public function access() {
     // If a block has no roles associated, it is displayed for every role.
     // For blocks with roles associated, if none of the user's roles matches
     // the settings from this block, access is denied.
-    $visibility = $this->entity->get('visibility');
+    $visibility = $this->configuration['visibility'];
     if (!empty($visibility['role']['roles']) && !array_intersect(array_filter($visibility['role']['roles']), array_keys($user->roles))) {
       // No match.
       return FALSE;
@@ -202,7 +185,7 @@ public function access() {
 
     // Check other modules for block access rules.
     foreach (module_implements('block_access') as $module) {
-      if (module_invoke($module, 'block_access', $this->entity) === FALSE) {
+      if (module_invoke($module, 'block_access', $this) === FALSE) {
         return FALSE;
       }
     }
@@ -489,4 +472,40 @@ public function submit($form, &$form_state) {
    */
   public function blockSubmit($form, &$form_state) {}
 
+  /**
+   * Implements \Drupal\block\BlockInterface::build().
+   */
+  public function build() {
+    $build = array();
+    $content = array();
+    if ($content = $this->blockBuild()) {
+      // @todo http://drupal.org/node/1942286
+      $build = array(
+        '#block' => (object) $this->getConfig(),
+        '#theme_wrappers' => array('block'),
+      );
+      // The label is the only string we actually render, so we need to handle
+      // it specially.
+      // @todo: Give the implications of this line further thought in
+      // http://drupal.org/node/1941244.
+      $build['#block']->label = check_plain($this->configuration['label']);
+    }
+    $build['content'] = $content;
+
+    // All blocks, even when empty, should be available for altering.
+    $id = str_replace(':', '__', $this->configuration['plugin']);
+    drupal_alter(array('block_view', "block_view_$id"), $build, $this);
+    return $build;
+  }
+
+  /**
+   * Builds the renderable array of the block's content.
+   *
+   * @return array
+   *   A renderable array representing the content of the block.
+   *
+   * @see \Drupal\block\BlockRenderController
+   */
+  abstract protected function blockBuild();
+
 }
diff --git a/core/modules/block/lib/Drupal/block/BlockInterface.php b/core/modules/block/lib/Drupal/block/BlockInterface.php
index 65bdee3..137c878 100644
--- a/core/modules/block/lib/Drupal/block/BlockInterface.php
+++ b/core/modules/block/lib/Drupal/block/BlockInterface.php
@@ -96,7 +96,7 @@ public function submit($form, &$form_state);
    * Builds and returns the renderable array for this block plugin.
    *
    * @return array
-   *   A renderable array representing the content of the block.
+   *   A renderable array for wrapping the content of the block.
    *
    * @see \Drupal\block\BlockRenderController
    */
diff --git a/core/modules/block/lib/Drupal/block/BlockRenderController.php b/core/modules/block/lib/Drupal/block/BlockRenderController.php
index e1c560e..5d3eefa 100644
--- a/core/modules/block/lib/Drupal/block/BlockRenderController.php
+++ b/core/modules/block/lib/Drupal/block/BlockRenderController.php
@@ -23,42 +23,6 @@ public function buildContent(array $entities, array $displays, $view_mode, $lang
   }
 
   /**
-   * Provides entity-specific defaults to the build process.
-   *
-   * @param Drupal\Core\Entity\EntityInterface $entity
-   *   The entity for which the defaults should be provided.
-   * @param string $view_mode
-   *   The view mode that should be used.
-   * @param string $langcode
-   *   (optional) For which language the entity should be prepared, defaults to
-   *   the current content language.
-   *
-   * @return array
-   *   An array of defaults to add into the entity render array.
-   */
-  protected function getBuildDefaults(EntityInterface $entity, $view_mode, $langcode) {
-    // @todo \Drupal\block\Tests\BlockTest::testCustomBlock() assuemes that a
-    //   block can be rendered without any of its wrappers. To do so, it uses a
-    //   custom view mode, and we choose to only add the wrappers on the default
-    //   view mode, 'block'.
-    if ($view_mode != 'block') {
-      return array();
-    }
-
-    return array(
-      '#block' => $entity,
-      '#weight' => $entity->get('weight'),
-      '#theme_wrappers' => array('block'),
-      '#block_config' => array(
-        'id' => $entity->get('plugin'),
-        'region' => $entity->get('region'),
-        'module' => $entity->get('module'),
-        'label' => check_plain($entity->label()),
-      ),
-    );
-  }
-
-  /**
    * Implements Drupal\Core\Entity\EntityRenderControllerInterface::view().
    */
   public function view(EntityInterface $entity, $view_mode = 'full', $langcode = NULL) {
@@ -73,15 +37,13 @@ public function viewMultiple(array $entities = array(), $view_mode = 'full', $la
     $build = array();
     foreach ($entities as $entity_id => $entity) {
       // Allow blocks to be empty, do not add in the defaults.
-      if ($content = $entity->getPlugin()->build()) {
-        $build[$entity_id] = $this->getBuildDefaults($entity, $view_mode, $langcode);
-      }
-      $build[$entity_id]['content'] = $content;
+      $build[$entity_id] = $entity->getPlugin()->build();
+      $build[$entity_id]['#weight'] = $entity->get('weight');
 
-      // All blocks, even when empty, should be available for altering.
-      $id = str_replace(':', '__', $entity->get('plugin'));
-      list(, $name) = $entity->id();
-      drupal_alter(array('block_view', "block_view_$id", "block_view_$name"), $build[$entity_id], $entity);
+      // Separate the theme and machine name components from the entity id.
+      list(, $name) = explode('.', $entity->id());
+      $plugin = $entity->getPlugin();
+      drupal_alter(array("block_view_$name"), $build[$entity_id], $plugin);
 
     }
     return $build;
diff --git a/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php b/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
index 75d82e8..009c1a6 100644
--- a/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
+++ b/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
@@ -123,8 +123,16 @@ public function getPlugin() {
 
       // Create a plugin instance and store its configuration as settings.
       try {
-        $this->instance = drupal_container()->get('plugin.manager.block')->createInstance($this->plugin, $this->settings, $this);
-        $this->settings += $this->instance->getConfig();
+        $properties = $this->getExportProperties();
+        unset($properties['settings']);
+        $this->instance = \Drupal::service('plugin.manager.block')->createInstance($this->plugin);
+        $this->instance->getConfig();
+        foreach ($properties as $key => $value) {
+          $this->instance->setConfig($key, $value);
+        }
+        foreach ($this->settings as $key => $value) {
+          $this->instance->setConfig($key, $value);
+        }
       }
       catch (PluginException $e) {
         // Ignore blocks belonging to disabled modules, but re-throw valid
@@ -138,6 +146,14 @@ public function getPlugin() {
   }
 
   /**
+   * Overrides \Drupal\Core\Entity\EntityInterface::label().
+   */
+  public function label($langcode = NULL) {
+    $configuration = $this->getPlugin()->getConfig();
+    return $configuration['label'];
+  }
+
+  /**
    * Overrides \Drupal\Core\Entity\Entity::uri();
    */
   public function uri() {
@@ -159,14 +175,73 @@ public function get($property_name, $langcode = NULL) {
     if ($property_name == 'theme' && !$value) {
       list($value) = explode('.', $this->id());
     }
+    elseif (!in_array($property_name, $this->exportProperties())) {
+      // Support geting plugin-specific settings with the get() method.
+      $settings = parent::get('settings');
+      if (isset($settings[$property_name])) {
+        $value = $settings[$property_name];
+      }
+    }
     return $value;
   }
 
   /**
-   * Overrides \Drupal\Core\Config\Entity\ConfigEntityBase::getExportProperties();
+   * Overrides \Drupal\Core\Config\Entity\ConfigEntityBase::set();
+   *
+   * The plugin configuration is the canonical source for any configuration
+   * within the plugin. The plugin does not care about the storage mechanism,
+   * so the entity must maintain both its own properties as well as the
+   * configuration of the plugin.
+   *
+   * Any property that exists in Block::exportProperties() can be handled by
+   * the parent method, with the exception of the settings property. Any property
+   * that is not documented in Block::exportProperties() is to be considered an
+   * internal configuration property of the plugin and should be maintained on
+   * the entity within the settings property. Setting of the settings property
+   * directly is supported, but all set() calls to the settings property are
+   * additive and will not remove settings values.
+   *
+   * @todo The basic functionality of this cannot change. The plugin
+   * configuration and entity values must always be up to date, but we should
+   * revisit whether this can be simplified. http://drupal.org/node/1942262
    */
-  public function getExportProperties() {
-    $names = array(
+  public function set($property_name, $value) {
+    if (!in_array($property_name, $this->exportProperties()) && $property_name != 'settings') {
+      // If the property is not a property of the entity, assume it belongs in
+      // the settings property of the entity, and set the plugin configuration
+      // value appropriately.
+      $settings = $this->get('settings');
+      $settings[$property_name] = $value;
+      $this->getPlugin()->setConfig($property_name, $value);
+      parent::set('settings', $settings);
+    }
+    elseif ($property_name == 'settings' && is_array($value)) {
+      // If we are updating the settings property and the value passed was an
+      // array, add each of the key value pairs to the plugin configuration and
+      // set the entity's 'settings' property.
+      $settings = $this->get('settings');
+      foreach ($value as $key => $key_value) {
+        $this->getPlugin()->setConfig($key, $key_value);
+        $settings[$key] = $key_value;
+      }
+      parent::set('settings', $settings);
+    }
+    else {
+      // If we're updating a property of the entity, just add the value to the
+      // plugin configuration as well.
+      $this->getPlugin()->setConfig($property_name, $value);
+      parent::set($property_name, $value);
+    }
+  }
+
+  /**
+   * Returns a list of properties to export for this entity.
+   *
+   * @return array
+   *   A simple array of property names on this entity.
+   */
+  protected function exportProperties() {
+    return array(
       'id',
       'label',
       'uuid',
@@ -179,11 +254,27 @@ public function getExportProperties() {
       'settings',
       'langcode',
     );
+  }
+
+  /**
+   * Overrides \Drupal\Core\Config\Entity\ConfigEntityBase::getExportProperties();
+   */
+  public function getExportProperties() {
     $properties = array();
-    foreach ($names as $name) {
+    foreach ($this->exportProperties() as $name) {
       $properties[$name] = $this->get($name);
     }
     return $properties;
   }
 
+  /**
+   * Implements \Drupal\Core\Entity\EntityInterface::save().
+   */
+  public function save() {
+    // Get any key value pairs in the plugin configuration that are not in the
+    // entity's properties and add them to the entity's settings property.
+    $this->settings = array_diff_key($this->getPlugin()->getConfig(), $this->getExportProperties());
+    return parent::save();
+  }
+
 }
diff --git a/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php b/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php
index d5dedb9..228f3db 100644
--- a/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php
+++ b/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php
@@ -35,14 +35,7 @@ public function __construct(array $namespaces) {
     $this->discovery = new DerivativeDiscoveryDecorator($this->discovery);
     $this->discovery = new AlterDecorator($this->discovery, 'block');
     $this->discovery = new CacheDecorator($this->discovery, 'block_plugins:' . language(LANGUAGE_TYPE_INTERFACE)->langcode, 'cache_block', CacheBackendInterface::CACHE_PERMANENT, array('block'));
-  }
-
-  /**
-   * Overrides \Drupal\Component\Plugin\PluginManagerBase::createInstance().
-   */
-  public function createInstance($plugin_id, array $configuration = array(), Block $entity = NULL) {
-    $plugin_class = DefaultFactory::getPluginClass($plugin_id, $this->discovery);
-    return new $plugin_class($configuration, $plugin_id, $this->discovery, $entity);
+    $this->factory = new DefaultFactory($this);
   }
 
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
index d707c80..10ad233 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
@@ -44,12 +44,8 @@ function testBlockThemeHookSuggestions() {
     ));
 
     $variables = array();
-    $variables['elements']['#block'] = $block;
-    $variables['elements']['#block_config'] = $block->getPlugin()->getConfig() + array(
-      'id' => $block->get('plugin'),
-      'region' => $block->get('region'),
-      'module' => $block->get('module'),
-    );
+    // @todo http://drupal.org/node/1942286
+    $variables['elements']['#block'] = (object) $block->getPlugin()->getConfig();
     $variables['elements']['#children'] = '';
     // Test adding a class to the block content.
     $variables['content_attributes']['class'][] = 'test-class';
diff --git a/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php b/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php
index dd7a423..6484840 100644
--- a/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php
+++ b/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php
@@ -34,9 +34,9 @@ public function settings() {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(
       '#children' => state()->get('block_test.content'),
     );
diff --git a/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php b/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php
index 165c798..9f44c72 100644
--- a/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php
+++ b/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php
@@ -59,9 +59,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $current_bid = 0;
     if ($node = menu_get_object()) {
       $current_bid = empty($node->book['bid']) ? 0 : $node->book['bid'];
diff --git a/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php b/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php
index bd7b49b..ea804a8 100644
--- a/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php
+++ b/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php
@@ -59,9 +59,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(
       '#theme' => 'comment_block',
       '#number' => $this->configuration['block_count'],
diff --git a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php
index e3ff7dd..a5611d3 100644
--- a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php
+++ b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php
@@ -22,9 +22,9 @@
 class ActiveTopicsBlock extends ForumBlockBase {
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $query = db_select('forum_index', 'f')
       ->fields('f')
       ->addTag('node_access')
diff --git a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php
index 71d4c3b..7b70836 100644
--- a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php
+++ b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php
@@ -22,9 +22,9 @@
 class NewTopicsBlock extends ForumBlockBase {
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $query = db_select('forum_index', 'f')
       ->fields('f')
       ->addTag('node_access')
diff --git a/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php b/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php
index 53c58e7..9e9caee 100644
--- a/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php
+++ b/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php
@@ -31,9 +31,9 @@ function blockAccess() {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $build = array();
     $path = drupal_is_front_page() ? '<front>' : current_path();
     list($plugin_id, $type) = explode(':', $this->getPluginId());
diff --git a/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php b/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php
index c535fc6..72a0474 100644
--- a/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php
+++ b/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php
@@ -24,9 +24,9 @@
 class MenuBlock extends SystemMenuBlock {
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     list($plugin, $menu) = explode(':', $this->getPluginId());
     return menu_tree($menu);
   }
diff --git a/core/modules/menu/menu.module b/core/modules/menu/menu.module
index a4a6718..055f2be 100644
--- a/core/modules/menu/menu.module
+++ b/core/modules/menu/menu.module
@@ -12,7 +12,7 @@
  */
 
 use Drupal\Core\Entity\EntityInterface;
-use Drupal\block\Plugin\Core\Entity\Block;
+use Drupal\block\BlockInterface;
 use Drupal\system\Plugin\Core\Entity\Menu;
 use Drupal\system\Plugin\block\block\SystemMenuBlock;
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -412,9 +412,9 @@ function _menu_parents_recurse($tree, $menu_name, $indent, &$options, $exclude,
 /**
  * Implements hook_block_view_alter().
  */
-function menu_block_view_alter(array &$build, Block $block) {
+function menu_block_view_alter(array &$build, BlockInterface $block) {
   // Add contextual links for system menu blocks.
-  if ($block->getPlugin() instanceof SystemMenuBlock) {
+  if ($block instanceof SystemMenuBlock) {
     foreach (element_children($build['content']) as $key) {
       $build['#contextual_links']['menu'] = array('admin/structure/menu/manage', array($build['content'][$key]['#original_link']['menu_name']));
     }
diff --git a/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php b/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php
index 083a096..befae9a 100644
--- a/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php
+++ b/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php
@@ -59,9 +59,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     if ($nodes = node_get_recent($this->configuration['block_count'])) {
       return array(
         '#theme' => 'node_recent_block',
diff --git a/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php b/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php
index af627a2..246eff2 100644
--- a/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php
+++ b/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php
@@ -39,9 +39,9 @@ public function blockAccess() {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(
       '#theme' => 'feed_icon',
       '#url' => 'rss.xml',
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index 6ce0874..f4d5e6b 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -2027,7 +2027,8 @@ function node_form_block_form_alter(&$form, &$form_state) {
  * if the visibility conditions are not met.
  */
 function node_block_access($block) {
-  $visibility = $block->get('visibility');
+  $configuration = $block->getConfig();
+  $visibility = $configuration['visibility'];
   if (!empty($visibility)) {
     $allowed_types = array();
     $node = menu_get_object();
diff --git a/core/modules/openid/openid.module b/core/modules/openid/openid.module
index 6d31124..1eb27e9 100644
--- a/core/modules/openid/openid.module
+++ b/core/modules/openid/openid.module
@@ -5,6 +5,8 @@
  * Implement OpenID Relying Party support for Drupal
  */
 
+use Drupal\block\BlockInterface;
+
 /**
  * Implements hook_menu().
  */
@@ -158,13 +160,13 @@ function openid_user_logout($account) {
 }
 
 /**
- * Implements hook_block_view_MODULE_DELTA_alter().
+ * Implements hook_block_view_ID_alter().
  *
  * Adds the OpenID login form to the user login block.
  *
  * @see \Drupal\user\Plugin\block\block\UserLoginBlock
  */
-function openid_block_view_user_login_block_alter(&$build, $block) {
+function openid_block_view_user_login_block_alter(&$build, BlockInterface $block) {
   // Only alter the block when it is non-empty, i.e. when no user is logged in.
   if (!isset($build['content']['user_login_form'])) {
     return;
diff --git a/core/modules/overlay/overlay.module b/core/modules/overlay/overlay.module
index cc29255..3ff93fe 100644
--- a/core/modules/overlay/overlay.module
+++ b/core/modules/overlay/overlay.module
@@ -486,7 +486,8 @@ function overlay_block_access($block) {
   // reason for duplicating effort here is performance; we do not even want
   // these blocks to be built if they are not going to be displayed.
   if ($regions_to_render = overlay_get_regions_to_render()) {
-    if (!in_array($block->get('region'), $regions_to_render)) {
+    $configuration = $block->getConfig();
+    if (!in_array($configuration['region'], $regions_to_render)) {
       return FALSE;
     }
   }
diff --git a/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php b/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php
index bb06d35..405d41e 100644
--- a/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php
+++ b/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php
@@ -30,9 +30,9 @@ public function blockAccess() {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(drupal_get_form('search_block_form'));
   }
 
diff --git a/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php b/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php
index f610717..937e16a 100644
--- a/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php
+++ b/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php
@@ -23,9 +23,9 @@
 class ShortcutsBlock extends BlockBase {
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(
       shortcut_renderable_links(shortcut_current_displayed_set()),
     );
diff --git a/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php b/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php
index 7417bd8..a2033f6 100644
--- a/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php
+++ b/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php
@@ -116,9 +116,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $content = array();
 
     if ($this->day_list) {
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php
index a5476c3..9621363 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php
@@ -38,9 +38,9 @@ public function blockAccess() {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(
       '#children' => $this->help,
     );
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php
index 80510b0..6b739ff 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php
@@ -23,9 +23,9 @@
 class SystemMainBlock extends BlockBase {
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(
       drupal_set_page_content()
     );
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php
index 721ae2e..c1fe3c9 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php
@@ -33,9 +33,9 @@ public function blockAccess() {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     list($plugin, $derivative) = explode(':', $this->getPluginId());
     // Derivatives are prefixed with 'menu-'.
     $menu = substr($derivative, 5);
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php
index 958edc0..68c062a 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php
@@ -23,9 +23,9 @@
 class SystemPoweredByBlock extends BlockBase {
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     return array(
       '#children' => theme('system_powered_by'),
     );
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 2c51ae0..ef46866 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -2645,7 +2645,7 @@ function system_preprocess_block(&$variables) {
 
     // System menu blocks should get the same class as menu module blocks.
     default:
-      if ($variables['elements']['#block']->getPlugin() instanceof SystemMenuBlock) {
+      if ($variables['elements']['#block']->plugin == 'system_main_block') {
         $variables['attributes_array']['role'] = 'navigation';
         $variables['classes_array'][] = 'block-menu';
       }
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php
index 716a315..bd293f5 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php
@@ -30,9 +30,9 @@ public function blockAccess() {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $form = drupal_get_form('user_login_form');
     unset($form['name']['#attributes']['autofocus']);
     unset($form['name']['#description']);
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
index 5f88f7f..4ee0547 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
@@ -62,9 +62,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     // Retrieve a list of new users who have accessed the site successfully.
     $items = db_query_range('SELECT uid, name FROM {users} WHERE status <> 0 AND access <> 0 ORDER BY created DESC', 0, $this->configuration['whois_new_count'])->fetchAll();
     $build = array(
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
index d88568a..db3433c 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
@@ -76,9 +76,9 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     // Count users active within the defined period.
     $interval = REQUEST_TIME - $this->configuration['seconds_online'];
 
diff --git a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php
index 4dbb64d..57289d7 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php
@@ -42,8 +42,8 @@ class ViewsBlock extends BlockBase {
   /**
    * Overrides \Drupal\Component\Plugin\PluginBase::__construct().
    */
-  public function __construct(array $configuration, $plugin_id, DiscoveryInterface $discovery, Block $entity) {
-    parent::__construct($configuration, $plugin_id, $discovery, $entity);
+  public function __construct(array $configuration, $plugin_id, DiscoveryInterface $discovery) {
+    parent::__construct($configuration, $plugin_id, $discovery);
 
     list($plugin, $delta) = explode(':', $this->getPluginId());
     list($name, $this->displayID) = explode('-', $delta, 2);
@@ -72,12 +72,12 @@ public function form($form, &$form_state) {
   }
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $output = $this->view->executeDisplay($this->displayID);
     // Set the label to the title configured in the view.
-    $this->entity->set('label', filter_xss_admin($this->view->getTitle()));
+    $this->configuration['label'] = filter_xss_admin($this->view->getTitle());
     // Before returning the block output, convert it to a renderable array
     // with contextual links.
     $this->addContextualLinks($output);
diff --git a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
index cb9d37c..b4fad38 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
@@ -23,9 +23,9 @@
 class ViewsExposedFilterBlock extends ViewsBlock {
 
   /**
-   * Implements \Drupal\block\BlockBase::build().
+   * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function build() {
+  public function blockBuild() {
     $output = $this->view->display_handler->viewExposedFormBlocks();
     // Before returning the block output, convert it to a renderable array with
     // contextual links.