A class can provide a public static factory method instead of a public constructor to allow clients to obtain an instance. This has both advantages and disadvantages, but should be a part of every programmer's toolkit.

## Advantages

### Static factory methods can have names

Static factory methods are advantageous because they have names and can replace multiple constructors with the same signature, making code easier to read.

### Static factory methods do not require to create a new object each time they're invoked

The advantages of static factory methods include their ability to return the same object from repeated invocations, and their ability to avoid creating unnecessary duplicate objects. This is especially useful for immutable classes, as it allows them to guarantee that no two equal instances exist. It also allows classes to be instance-controlled, which can be used to guarantee that they are singletons or noninstantiable, and to make sure that enums provide a guarantee of no two equal instances.

### Static factory methods can return an object of any subtype of their return type

A third advantage of state factory methods is that, unlike constructors, they can return an object of any subtype of their return type. This gives flexibility in choosing the class of the returned object and allows API's to return objects without making their classes public, reducing the size and complexity of the API. As of Java 8, static members of an interface are required to be public, but private static methods are allowed in Java 9.

### Static factory methods can return different types depending on the input parameters

Static factories provide the advantage of allowing the class of the returned object to vary from call to call as a function of the input parameters, and also from release to release. This makes it possible for implementations to change without affecting client code, which is beneficial for performance.

### Static factory methods can return objects for which there exists no class yet

The fifth advantage of static factories is that the class of the returned object need not exist when the class containing the method is written. This is important in service provider frameworks such as the Java Database Connectivity API (JDBC), which have three essential components: a service interface, a provider registration API, and a service access API, which may allow clients to cycle through all available implementations. An optional fourth component is a service provider interface, which describes a factory object for producing instances of the service interface. Java 6 includes a general-purpose service provider framework, java.util.ServiceLoader, which should be used instead of writing one's own.

## Disadvantages

### If no constructors are uses, the class cannot be subclassed

Static factory methods limit the ability to subclass classes without public or protected constructors, but they can encourage composition over inheritance and are required for immutable types.

### Static factory methods may are hard to find for programmers

Static factory methods are often preferred over public constructors as they are more concise and can be easier to find. Common names for these methods include \"valueOf\", \"of\", \"getInstance\", and \"newInstance\", and it is important to draw attention to them in API documentation.

Using static factory methods instead of constructors can have several advantages

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Static Factory Methods

## The case for the static site generator

More and more developers are jumping on the "go static train", and rightfully so. Static pages are fast, lightweight, they scale well. They are more secure, and simple to maintain and they allow you to focus all your time and effort on the user interface. Often times, this dedication really shows.

It just so happens that static site generators are mostly loved by developers, but not by the average Joe. They do not offer WYSIWYG, previewing on demo sites may take an update cycle, they are often based on markdown text files, and they require some knowledge of modern day repositories.

Moreover, when teams are collaborating, it can get complicated quickly. Has this article already been proof-read or reviewed? Is this input valid? Are user permissions available, e.g. for administering adding and removing team members? Can this article be published at a future date? How can a large repository of content be categorized, organized, and searched? All these requirements have previously been more or less solved within the admin area of your CMS. But of course with all the baggage that made you leave the appserver-app-database-in-one-big-blob stack in the first place.

## Content APIs to the rescue

An alternative is decoupling the content management aspect from the system. And then replacing the maintenance prone server with a cloud based web service offering. Effectively, instead of your CMS of old, you move to a [Content Management as a Service (CMaaS)](https://www.contentful.com/r/knowledgebase/content-as-a-service/ "Content Management as a Service (CMaaS)") world, with a content API to deliver all your content. That way, you get the all the [benefits of content management features](http://www.digett.com/blog/01/16/2014/pairing-static-websites-cms "benefits of content management features") while still being able to embrace the static site generator mantra.

It so happens that Contentful is offering just that kind of content API. A service that

* from the ground up has been designed to be fast, scalable, secure, and offer high uptime, so that you don’t have to worry about maintenance ever again.
* offers a powerful editor and lots of flexibility in creating templates for your documents that your editors can reuse and combine, so that no developers resources are required in everyday writing and updating tasks.
* separates content from presentation, so you can reuse your content repository for any device platform your heart desires. That way, you can COPE ("create once, publish everywhere").
* offers webhooks that you can use to rebuild your static site in a fully automated fashion every time your content is modified.

Extracted from the article [CMS-functionality for static site generators](https://www.contentful.com/r/knowledgebase/contentful-api-cms-static-site-generators/ "CMS-functionality for static site generators"). Read more about the [static site generators supported by Contentful](https://www.contentful.com/developers/docs/tools/staticsitegenerators/ "static site generators supported by Contentful").

Worry less about security, caching, and talking to the server. Static sites are the new thing.

Static sites are great

These is your very first content with Contentful, pulled in JSON format using the [Content Delivery API](https://www.contentful.com/developers/docs/references/content-delivery-api/ "Content Delivery API"). Content and presentation are now decoupled, allowing you to focus your efforts in building the perfect app.

## Your first steps

Building with Contentful is easy. First take a moment to get [the basics of content modelling](https://www.contentful.com/r/knowledgebase/content-modelling-basics/ "the basics of content modelling"), which you can set up in the [Contentful Web app](https://app.contentful.com/ "Contentful Web app"). Once you get that, feel free to drop by the [Documentation](https://www.contentful.com/developers/docs/ "Documentation") to learn a bit more about how to build your app with Contentful, in particular the [API basics](https://www.contentful.com/developers/docs/concepts/apis/ "API basics") and each one of our four APIs, as shown below.

### Content Delivery API

The [Content Delivery API](https://www.contentful.com/developers/docs/references/content-delivery-api/ "Content Delivery API") (CDA), available at `cdn.contentful.com`, is a read-only API for delivering content from Contentful to apps, websites and other media. Content is delivered as JSON data, and images, videos and other media as files.
The API is available via a globally distributed content delivery network. The server closest to the user serves all content, both JSON and binary. This minimizes latency, which especially benefits mobile apps. Hosting content in multiple global data centers also greatly improves the availability of content.

### Content Management API

The [Content Management API](https://www.contentful.com/developers/docs/references/content-management-api/ "Content Management API") (CMA), available at `api.contentful.com`, is a read-write API for managing content. Unlike the Content Delivery API, the management API requires you to authenticate as a Contentful user. You could use the CMA for several use cases, such as:
* Automatic imports from different CMSes like WordPress or Drupal.
* Integration with other backend systems, such as an e-commerce shop.
* Building custom editing experiences. We built the [Contentful Web app](https://app.contentful.com/ "Contentful Web app") on top of this API.

### Preview API

The [Content Preview API](https://www.contentful.com/developers/docs/concepts/apis/#content-preview-api "Content Preview API"), available at `preview.contentful.com`, is a variant of the CDA for previewing your content before delivering it to your customers. You use the Content Preview API in combination with a "preview" deployment of your website (or a "preview" build of your mobile app) that allows content managers and authors to view their work in-context, as if it were published, using a "preview" access token as though it were delivered by the CDA.

### Images API

The [Images API](https://www.contentful.com/developers/docs/concepts/apis/#images-api "Images API"), available at `images.contentful.com`, allows you to resize and crop images, change their background color and convert them to different formats. Using our API for these transformations lets you upload high-quality assets, deliver exactly what your app needs, and still get all the benefits of our caching CDN.

Your very first content with Contentful, pulled in JSON format using the Content Delivery API.

Blog

Static Factory Methods

Static sites are great

Hello world

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