Programmatically Node load and Multiple Node load in drupal 8.

In drupal 7, we have node_load($nodeid) for load the node but now in drupal 8 syntax is changed and now node load by Node::load($nodeid) or Add the name space at the top of the page. \Drupal\node\Entity\Node::load($nodeid);

If we are using Symfony library and calling name space

use Drupal\node\Entity\Node;

So we do not need to use node class in node::load, we just need the syntax like Node::load($nodeid);

but if we are not calling or render name space then for node load we need to use the syntax like

\Drupal\node\Entity\Node::load($nodeid);

For get the node detail fields by Node::load($nodeid) syntax is..

Example: This example is for single node load.

              $node_detail = Node::load($nodeid);

                                   OR

              $node_detail = \Drupal\node\Entity\Node::load($nodeid);

              $node_id = $node_detail->id();

              $node_title = $node_detail->getTitle();

              $node_status = $node_detail->isPublished();

              $node_type = $node_detail->type->target_id; 

              $node_field_select_id = $node_detail->get('field_machine_name')->target_id;

              $node_field_select_value = $node_detail->get('field_machine_name')->value;

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In drupal 8 for load multiple nodes of any `Content Type`, we have Node::loadMultiple() and Drupal::entityQuery() functions for load all the nodes of given content type. We have an Example with Syntax for this, please have a look.
Syntax:
$all_nids = \Drupal::entityQuery('node')->condition('type','write content type machine name ')->execute();

Then pass the $get_all_nids variable to Node::loadMultiple function for get data..

$nodes = \Drupal\node\Entity\Node::loadMultiple($get_all_nids);

Example:
    $nids = \Drupal::entityQuery('node')->condition('type','applications')->execute(); // There application is my content type machine name..
    $node_detail = \Drupal\node\Entity\Node::loadMultiple($nids);
    foreach ($node_detail as $node){  // In node_detail array we have all nodes details..
        // here we are fetching fields detail.
        $title = $node->getTitle();
        $application_category_id = $node->field_application_category->target_id;       
        $img = file_create_url($node->field_application_image->entity->getFileUri());
        $image_gallery .='<div class ="imggallery"><img src="'.$img.'"><p>'.$title.'</p></div>';
    }
    // here returning $image_gallery array with image_gallery detail.
    return array(
    '#markup' => t($image_gallery),
    );       

   
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