re:</p>
<ul>
<li>Lazily instantiated – Angular only instantiates a service when an application component depends
on it.</li>
<li>Singletons – Each component dependent on a service gets a reference to the single instance
generated by the service factory.</li>
</ul>
<p>Angular offers several useful services (like <a href="api/ng/service/$http"><code>$http</code></a>), but for most applications
you&#39;ll also want to <a href="guide/services#creating-services">create your own</a>.</p>
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