You do not have permission to edit this page, for the following reasons:

This IP address has been blocked from editing Wikipedia.
This does not affect your ability to read Wikipedia pages.
Most people who see this message have done nothing wrong. Some kinds of blocks restrict editing from specific service providers or telecom companies in response to recent abuse or vandalism, and can sometimes affect other users who are unrelated to that abuse. Review the information below for assistance if you do not believe that you have done anything wrong.

The IP address or range 54.161.0.0/16 has been blocked (disabled) by ‪Blablubbs‬ for the following reason(s):

The IP address that you are currently using has been blocked because it is believed to be a web host provider or colocation provider. To prevent abuse, web hosts and colocation providers may be blocked from editing Wikipedia.
You will not be able to edit Wikipedia using a web host or colocation provider because it hides your IP address, much like a proxy or VPN.
We recommend that you attempt to use another connection to edit. For example, if you use a proxy or VPN to connect to the internet, turn it off when editing Wikipedia. If you edit using a mobile connection, try using a Wi-Fi connection, and vice versa. If you are using a corporate internet connection, switch to a different Wi-Fi network. If you have a Wikipedia account, please log in.
If you do not have any other way to edit Wikipedia, you will need to request an IP block exemption.

How to appeal if you are confident that your connection does not use a colocation provider's IP address:
If you are confident that you are not using a web host, you may appeal this block by adding the following text on your talk page: ((unblock|reason=Caught by a colocation web host block but this host or IP is not a web host. My IP address is _______. Place any further information here. ~~~~)). You must fill in the blank with your IP address for this block to be investigated. Your IP address can be determined here. Alternatively, if you wish to keep your IP address private you can use the unblock ticket request system. There are several reasons you might be editing using the IP address of a web host or colocation provider (such as if you are using VPN software or a business network); please use this method of appeal only if you think your IP address is in fact not a web host or colocation provider.

Administrators: The IP block exemption user right should only be applied to allow users to edit using web host in exceptional circumstances, and requests should usually be directed to the functionaries team via email. If you intend to give the IPBE user right, a CheckUser needs to take a look at the account. This can be requested most easily at SPI Quick Checkuser Requests. Unblocking an IP or IP range with this template is highly discouraged without at least contacting the blocking administrator.

This block will expire on 10:07, 1 October 2024.

Even when blocked, you will usually still be able to edit your user talk page, as well as email administrators and other editors.

For information on how to proceed, please read the FAQ for blocked users and the guideline on block appeals. The guide to appealing blocks may also be helpful.

Other useful links: Blocking policy · Help:I have been blocked
Your IP address is in a range that has been blocked on all Wikimedia Foundation wikis. The block was made by ‪Jon Kolbert‬. The reason given is Open proxy/Webhost: See the help page if you are affected .
- Start of block: 18:27, 12 November 2023
- Expiry of block: 18:27, 12 November 2028
Your current IP address is 54.161.166.4. The blocked range is 54.161.0.0/16. Please include all above details in any queries you make. If you believe you were blocked by mistake, you can find additional information and instructions in the No open proxies global policy. Otherwise, to discuss the block please post a request for review on Meta-Wiki. You could also send an email to the stewards VRT queue at stewards@wikimedia.org including all above details.

You can view and copy the source of this page:

((short description|Code that has to be included in many places with little or no alteration))
((More citations needed|date=May 2017))
In computer programming, '''boilerplate code''', or simply '''boilerplate''', are sections of code that are repeated in multiple places with little to no variation. When using languages that are considered ''verbose'', the programmer must write a lot of boilerplate code to accomplish only minor functionality.<ref>((cite book |last1=Lämmel |first1=Ralf |last2=Jones |first2=Simon Peyton |date=2003 |chapter=Scrap your boilerplate: a practical design pattern for generic programming |title=Proceedings of the 2003 ACM SIGPLAN International Workshop on Types in Languages Design and Implementation |series=TLDI '03 |location=New York |publisher=[[Association for Computing Machinery|ACM]] |pages=26–37 |isbn=9781581136494 |doi=10.1145/604174.604179 |s2cid=9472305 |chapter-url=https://www.researchgate.net/publication/221282345))</ref>

The need for boilerplate can be reduced through high-level mechanisms such as [[metaprogramming]] (which has the computer automatically write the needed boilerplate code or insert it at [[compile time]]), [[convention over configuration]] (which provides good default values, reducing the need to specify program details in every project) and [[model-driven engineering]] (which uses models and model-to-code generators, eliminating the need for manual boilerplate code).

== Origin ==
((further|Boilerplate (text)))

The term arose from the [[newspaper]] business. Columns and other pieces that were distributed by [[print syndication|print syndicate]]s were sent to subscribing newspapers in the form of prepared [[printing plate]]s. Because of their resemblance to the metal plates used in the making of [[boiler]]s, they became known as "boiler plates", and their resulting text—"boilerplate text". As the stories that were distributed by boiler plates were usually "[[filler (media)|fillers]]" rather than "serious" news, the term became synonymous with unoriginal, repeated text.<ref>((cite web |url=https://www.dictionary.com/browse/boilerplate |title=Boilerplate |website=Dictionary.com |access-date=2018-01-27))</ref><ref>((cite web |url=https://www.merriam-webster.com/dictionary/boilerplate |title=Boilerplate |website=Merriam-Webster |language=en |access-date=2018-01-27))</ref>

A related term is ''bookkeeping code'', referring to code that is not part of the [[business logic]] but is interleaved with it in order to keep data structures updated or handle secondary [[aspect (computer programming)|aspects]] of the program.

== Preamble ==
One form of boilerplate consists of declarations which, while not part of the program logic or the language's essential [[syntax (programming languages)|syntax]], are added to the start of a source file as a matter of custom. The following [[Perl]] example demonstrates boilerplate:

<syntaxhighlight lang="perl">
#!/usr/bin/perl
use warnings;
use strict;
</syntaxhighlight>

The first line is a [[shebang (Unix)|shebang]], which identifies the file as a Perl script that can be executed directly on the command line on Unix/Linux systems. The other two are [[directive (programming)|pragma]]s turning on warnings and strict mode, which are mandated by fashionable Perl [[programming style]].

This next example is a C/C++ [[programming language]] boilerplate, [[include guard|<code>#include</code> guard]].

<syntaxhighlight lang="CPP">
#ifndef MYINTERFACE_H
#define MYINTERFACE_H

...

#endif
</syntaxhighlight>

This checks, and sets up, a global flag to tell the compiler whether the file myinterface.h has already been included. As many interdepending files may be involved in the compilation of a module, this avoids processing the same header multiple times, (which would lead to errors due to multiple definitions with the same name).

== In Java and similar platforms ==

In [[Java (programming language)|Java]] programs, [[Data transfer object|DTO]] classes are often provided with methods for [[mutator method|getting and setting]] instance variables. The definitions of these methods can frequently be regarded as boilerplate. Although the code will vary from one class to another, it is sufficiently stereotypical in structure that it would be better generated automatically than written by hand. For example, in the following [[Java (programming language)|Java]] class representing a pet, almost all the code is boilerplate except for the [[declaration (computer programming)|declaration]]s of ''Pet'', ''name'', and ''owner'':

=== Java ===

<syntaxhighlight lang="Java">
public class Pet {
    private String name;
    private Person owner;

    public Pet(String name, Person owner) {
        this.name = name;
        this.owner = owner;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Person getOwner() {
        return owner;
    }

    public void setOwner(Person owner) {
        this.owner = owner;
    }
}
</syntaxhighlight>

Most of the boilerplate in this example exists to fulfill requirements of [[JavaBeans]]. If the variable's '''name''' and '''owner''' were declared as [[List of Java keywords|public]], the [[Method (computer programming)#Accessor.2C mutator and manager methods|accessor and mutator methods]] would not be needed.

In Java 14, record classes were added to fight with this issue.<ref>((cite web |title=Record Classes |url=https://docs.oracle.com/en/java/javase/20/language/records.html |website=docs.oracle.com))</ref><ref>((cite web |title=JEP 395: Record |url=https://openjdk.org/jeps/395 |website=openjdk.org))</ref><ref>((cite web |last=Evans |first=Ben| date=2020-11-01 |title=Records Come to Java |url=https://blogs.oracle.com/javamagazine/post/records-come-to-java |website=blogs.oracle.com))</ref>

To reduce the amount of boilerplate, many frameworks have been developed, e.g. Lombok for Java.<ref>((cite web |last=Frankel |first=Nicolas |date=2009-12-07 |title=Lombok reduces your boilerplate code |url=https://dzone.com/articles/lombok-reduces-your |website=DZone.com |access-date=2017-08-02))</ref> The same code as above is auto-generated by Lombok using [[Java annotation]]s, which is a form of [[metaprogramming]]:

<syntaxhighlight lang="Java">
@AllArgsConstructor
@Getter
@Setter
public class Pet {
    private String name;
    private Person owner;
}

</syntaxhighlight>

=== Scala ===

In some other programming languages it may be possible to achieve the same thing with less boilerplate, when the language has built-in support for such common constructs. For example, the equivalent of the above Java code can be expressed in [[Scala (programming language)|Scala]] using just one line of code:

<syntaxhighlight lang="Scala">
case class Pet(var name: String, var owner: Person)
</syntaxhighlight>

=== C# ===

Or in [[C Sharp (programming language)|C#]] using Automatic [[Property (programming)|Properties]] with compiler generated backing fields:

<syntaxhighlight lang="csharp">
public class Pet
{
    public string Name { get; set; }
    public Person Owner { get; set; }
}
</syntaxhighlight>

Starting with C# 9.0 there is an opportunity to use Records which generate classes with Properties automatically:

<syntaxhighlight lang="csharp">
public record Pet(string Name, Person Owner);
</syntaxhighlight>

=== Method boilerplate ===
In addition to declarations, [[method (computer programming)|method]]s in OOP languages also contribute to the amount of boilerplate. A 2015 study on popular Java projects shows that 60% of methods can be uniquely identified by the occurrence of 4.6% of its tokens, making the remaining 95.4% boilerplate irrelevant to logic. The researchers believe this result would translate to [[subroutine]]s in procedural languages in general.<ref>((cite arXiv |author1=Martin Velez |author2=Dong Qiu |author3=You Zhou |author4=Earl T. Barr |author5=Zhendong Su |eprint=1502.01410 |title= On the Lexical Distinguishability of Source Code [was: A Study of "Wheat" and "Chaff" in Source Code] |class=cs |date=5 Feb 2015))</ref>

== HTML ==
In [[HTML]], the following boilerplate is used as a basic empty template and is present in most web pages:
<syntaxhighlight lang="html">
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8"/>
  <title>Test</title>
</head>
<body>

</body>
</html>
</syntaxhighlight>
The [[WHATWG]] HTML Living Standard defines that the ((Tag|html|o)), ((Tag|head|o)) and ((Tag|body|o)) tags may be safely omitted under most circumstances.<ref>((Cite web|url=https://html.spec.whatwg.org/multipage/syntax.html#syntax-tag-omission|title=HTML Standard - The HTML syntax - Optional tags|date=2017-05-05|website=WHATWG|access-date=2017-05-05))</ref> The ((Code|<meta charset((=))"UTF-8">|html)) tag is technically redundant when coming directly from a web server configured to send the character encoding in an HTTP header, though it becomes useful when the HTML response is saved in an <code>.html</code> file, cache, or web archive.<ref>((Cite web|url=https://stackoverflow.com/q/14669352|title=Is the charset meta tag required with HTML5?|website=stackoverflow.com|access-date=2017-05-05))</ref> [[Google]]'s HTML/CSS style guide recommends that all optional tags be omitted,<ref>((Cite web|url=https://google.github.io/styleguide/htmlcssguide.html#Optional_Tags|title=Google HTML/CSS Style Guide|website=google.github.io|language=en|access-date=2017-05-05))</ref> resulting in much less boilerplate. The [[World Wide Web Consortium]] states that the element ((Tag|title|o)) must not be empty:<ref>((Cite web|url=https://www.w3.org/WAI/standards-guidelines/act/rules/html-page-non-empty-title-2779a5|title=HTML page has non-empty title|website=www.w3.org|language=en| accessdate=22 July 2021))</ref>
<syntaxhighlight lang="html">
<!DOCTYPE html>
<title>Test</title>
</syntaxhighlight>

== Python ==
In [[Python (programming language)|Python]], the following boilerplate code can be used to modify if code can only be executed in or out of a module context.
<syntaxhighlight lang="python">
if __name__ == '__main__':
    # Anything placed here will never be executed in a module context.
    pass

if __name__ != '__main__':
    # Anything placed here will only be executed in a module context.
    pass
</syntaxhighlight>

((Clear))

==See also==
((Div col))
* ((annotated link|Directive (programming)))
* ((annotated link|General-purpose macro processor))
* ((annotated link|"Hello, World!" program))
* ((annotated link|Library (computing)))
* ((annotated link|Macro (computer science)))
* ((annotated link|Preprocessor))
* ((annotated link|Scaffold (programming)))
* ((annotated link|Snippet (programming)))
* ((annotated link|Template processor))
* ((annotated link|Web template system))
((Div col end))

==References==
((Reflist))

[[Category:Source code]]
[[Category:Computer programming folklore]]
[[Category:Software engineering folklore]]
[[Category:Articles with example Java code]]

Pages transcluded onto the current version of this page (help):

"Hello, World!" program (view source) (semi-protected)
Boilerplate code (edit)
Directive (programming) (edit)
General-purpose macro processor (edit)
Library (computing) (edit)
Macro (computer science) (edit)
Preprocessor (edit)
Scaffold (programming) (edit)
Snippet (programming) (edit)
Template processor (edit)
Web template system (edit)
Template:Ambox (view source) (template editor protected)
Template:Annotated link (view source) (template editor protected)
Template:Cite arXiv (view source) (template editor protected)
Template:Cite book (view source) (protected)
Template:Cite web (view source) (protected)
Template:Clear (view source) (protected)
Template:Code (view source) (template editor protected)
Template:Div col (view source) (template editor protected)
Template:Div col/styles.css (view source) (template editor protected)
Template:Div col end (view source) (template editor protected)
Template:Find sources mainspace (view source) (template editor protected)
Template:Further (view source) (template editor protected)
Template:Main other (view source) (protected)
Template:More citations needed (view source) (template editor protected)
Template:Pagetype (view source) (protected)
Template:Reflist (view source) (protected)
Template:Reflist/styles.css (view source) (protected)
Template:SDcat (view source) (template editor protected)
Template:Short description (view source) (protected)
Template:Short description/lowercasecheck (view source) (protected)
Template:Tag (view source) (template editor protected)
Module:Annotated link (view source) (template editor protected)
Module:Arguments (view source) (protected)
Module:Category handler (view source) (protected)
Module:Category handler/blacklist (view source) (protected)
Module:Category handler/config (view source) (protected)
Module:Category handler/data (view source) (protected)
Module:Category handler/shared (view source) (protected)
Module:Check for unknown parameters (view source) (protected)
Module:Citation/CS1 (view source) (protected)
Module:Citation/CS1/COinS (view source) (protected)
Module:Citation/CS1/Configuration (view source) (protected)
Module:Citation/CS1/Date validation (view source) (protected)
Module:Citation/CS1/Identifiers (view source) (protected)
Module:Citation/CS1/Utilities (view source) (protected)
Module:Citation/CS1/Whitelist (view source) (protected)
Module:Citation/CS1/styles.css (view source) (protected)
Module:Disambiguation/templates (view source) (protected)
Module:Find sources (view source) (template editor protected)
Module:Find sources/config (view source) (template editor protected)
Module:Find sources/links (view source) (template editor protected)
Module:Find sources/templates/Find sources mainspace (view source) (template editor protected)
Module:Format link (view source) (template editor protected)
Module:GetShortDescription (view source) (template editor protected)
Module:Hatnote (view source) (template editor protected)
Module:Hatnote/styles.css (view source) (template editor protected)
Module:Hatnote list (view source) (template editor protected)
Module:Labelled list hatnote (view source) (template editor protected)
Module:Lang (view source) (template editor protected)
Module:Lang/ISO 639 synonyms (view source) (template editor protected)
Module:Lang/data (view source) (template editor protected)
Module:Language/data/iana languages (view source) (template editor protected)
Module:Language/data/iana regions (view source) (template editor protected)
Module:Language/data/iana scripts (view source) (template editor protected)
Module:Language/data/iana suppressed scripts (view source) (template editor protected)
Module:Language/data/iana variants (view source) (template editor protected)
Module:Message box (view source) (protected)
Module:Message box/ambox.css (view source) (protected)
Module:Message box/configuration (view source) (protected)
Module:Namespace detect/config (view source) (protected)
Module:Namespace detect/data (view source) (protected)
Module:Pagetype (view source) (protected)
Module:Pagetype/config (view source) (protected)
Module:Pagetype/disambiguation (view source) (template editor protected)
Module:Pagetype/setindex (view source) (template editor protected)
Module:Pagetype/softredirect (view source) (template editor protected)
Module:SDcat (view source) (template editor protected)
Module:String (view source) (protected)
Module:Unicode data (view source) (template editor protected)
Module:Unsubst (view source) (protected)
Module:Wikitext Parsing (view source) (template editor protected)
Module:Yesno (view source) (protected)

Return to Boilerplate code.

Retrieved from "https://en.wikipedia.org/wiki/Boilerplate_code"