The object manager

The initializing of objects in Magento is done via what is called the object manager. The object manager itself is an instance of the Magento\Framework\ObjectManager\ObjectManager class that implements the Magento\Framework\ObjectManagerInterface class. The ObjectManager class defines the following three methods:

• create($type, array $arguments = []): This creates a new object instance
• get($type): This retrieves a cached object instance
• configure(array $configuration): This configures the di instance

The object manager can instantiate a PHP class, which can be a model, helper, or block object. Unless the class that we are working with has already received an instance of the object manager, we can receive it by passing ObjectManagerInterface into the class constructor, as follows:

public function __construct(
    \Magento\Framework\ObjectManagerInterface $objectManager
)
{
    $this->_objectManager = $objectManager;
}

Usually, we don't have to take care of the constructor...