= Contributing to Spring Boot

Spring Boot is released under the Apache 2.0 license. If you would like to contribute something, or want to hack on the code this document should help you get started.



== Code of Conduct
This project adheres to the Contributor Covenant link:CODE_OF_CONDUCT.adoc[code of conduct].
By participating, you are expected to uphold this code. Please report unacceptable behavior to spring-code-of-conduct@pivotal.io.



== Using GitHub Issues
We use GitHub issues to track bugs and enhancements.
If you have a general usage question please ask on https://stackoverflow.com[Stack Overflow].
The Spring Boot team and the broader community monitor the https://stackoverflow.com/tags/spring-boot[`spring-boot`] tag.

If you are reporting a bug, please help to speed up problem diagnosis by providing as much information as possible.
Ideally, that would include a small sample project that reproduces the problem.



== Reporting Security Vulnerabilities
If you think you have found a security vulnerability in Spring Boot please *DO NOT* disclose it publicly until we've had a chance to fix it.
Please don't report security vulnerabilities using GitHub issues, instead head over to https://spring.io/security-policy and learn how to disclose them responsibly.



== Sign the Contributor License Agreement
Before we accept a non-trivial patch or pull request we will need you to https://cla.pivotal.io/sign/spring[sign the Contributor License Agreement].
Signing the contributor's agreement does not grant anyone commit rights to the main repository, but it does mean that we can accept your contributions, and you will get an author credit if we do.
Active contributors might be asked to join the core team, and given the ability to merge pull requests.



== Code Conventions and Housekeeping
None of these is essential for a pull request, but they will all help.
They can also be added after the original pull request but before a merge.

* We use the https://github.com/spring-io/spring-javaformat/[Spring JavaFormat] project to apply code formatting conventions.
  If you use Eclipse and you follow the '`Importing into eclipse`' instructions below you should get project specific formatting automatically.
  You can also install the https://github.com/spring-io/spring-javaformat/#intellij-idea[Spring JavaFormat IntelliJ Plugin] or format the code from the Gradle build by running `./gradlew format`.
  Note that if you have format violations in `buildSrc`, you can fix them by running `./gradlew -p buildSrc format` from the project root directory.
* The build includes checkstyle rules for many of our code conventions. 
  Run `./gradlew checkstyleMain checkstyleTest` if you want to check your changes are compliant.
* Make sure all new `.java` files have a Javadoc class comment with at least an `@author` tag identifying you, and preferably at least a paragraph on what the class is for.
* Add the ASF license header comment to all new `.java` files (copy from existing files in the project).
* Add yourself as an `@author` to the `.java` files that you modify substantially (more than cosmetic changes).
* Add some Javadocs.
* A few unit tests would help a lot as well -- someone has to do it.
* If no-one else is using your branch, please rebase it against the current master (or other target branch in the main project).
* When writing a commit message please follow https://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html[these conventions].



== Working with the Code
If you don't have an IDE preference we would recommend that you use https://spring.io/tools/sts[Spring Tools Suite] or https://eclipse.org[Eclipse] when working with the code.
We use the https://projects.eclipse.org/projects/tools.buildship[Buildship] Eclipse plugin for Gradle support.
Other IDEs and tools should also work without issue.



=== Building from Source
Spring Boot source can be built from the command line using https://gradle.org[Gradle] on JDK 1.8 or above.
We include https://docs.gradle.org/current/userguide/gradle_wrapper.html[Gradle's wrapper scripts] (`./gradlew` or `gradlew.bat`) that you can run rather than needing to install Gradle locally.

The project can be built from the root directory using the standard Gradle command:

[indent=0]
----
	$ ./gradlew build
----



=== Importing into Eclipse
You can import the Spring Boot code into any Eclipse 2019-12-based distribution.
The easiest way to setup a new environment is to use the Eclipse Installer with the provided `spring-boot-project.setup` file (in the `/eclipse` folder).



==== Using the Eclipse Installer
Spring Boot includes a `.setup` files which can be used with the Eclipse Installer to provision a new environment.
To use the installer:

* Download and run the latest https://download.eclipse.org/justj/?file=oomph/products/latest[Eclipse Installer] (must be 1.19.0 or above).
* Switch to "Advanced Mode" using the drop down menu on the right.
* Select "`Eclipse IDE for Java Developers`" under "`Eclipse.org`" as the product to install, `2020-12` as the product version, and click "`next`".
* For the "`Project`" click on "`+`" to add a new setup file.
  Select "`Github Projects`" and browse for `<checkout>/eclipse/spring-boot-project.setup` from your locally cloned copy of the source code.
  Click "`OK`" to add the setup file to the list.
* Double-click on "`Spring Boot`" from the project list to add it to the list that will be provisioned then click "`Next`".
* Click show all variables and make sure that "`Checkout Location`" points to the locally cloned source code that you selected earlier.
  You might also want to pick a different install location here.
* Click "`Finish`" to install the software.

Once complete you should find that a local workspace has been provisioned complete with all required Eclipse plugins.
Projects will be grouped into working-sets to make the code easier to navigate.

TIP: If you see import errors with `com.sun` packages make sure you have setup a valid `JavaSE-1.8` environment. From preferences select "`Java`", "`Installed JREs`", "`Execution Environments`" and make sure "`JavaSE-1.8`" points to a Java 1.8 install (we use AdoptOpenJDK on our CI).



==== Manual Installation with Buildship
If you prefer to install Eclipse yourself you should use the https://projects.eclipse.org/projects/tools.buildship[Buildship] Eclipse plugin.
If you don't already have Buildship installed it is available from the "`Eclipse marketplace`".

Spring Boot includes project specific source formatting settings, in order to have these work with Buildship, we provide an additional Eclipse plugin that you can install.



===== Install the Spring Formatter plugin
* Select "`Help`" -> "`Install New Software`".
* Add `https://dl.bintray.com/spring/javaformat-eclipse/` as a site.
* Install "Spring Java Format".

NOTE: The plugin is optional.
Projects can be imported without the plugins, your code changes just won't be automatically formatted.

With the requisite Eclipse plugins installed you can select `Gradle -> Existing Gradle project` from the `File -> Import...` menu to import the code.



=== Importing into IntelliJ IDEA
If you have performed a checkout of this repository already, use "`File`" -> "`Open`" and then select the root `build.gradle` file to import the code.

Alternatively, you can let IntellIJ IDEA checkout the code for you. Use "`File`" -> "`New`" -> "`Project from Version Control`" and `https://github.com/spring-projects/spring-boot` for the URL. 
Once the checkout has completed, a pop-up will suggest to open the project.



==== Install the Spring Formatter plugin
If you haven't done so, install the formatter plugin so that proper formatting rules are applied automatically when you reformat code in the IDE.

* Download the latest https://search.maven.org/search?q=g:io.spring.javaformat%20AND%20a:spring-javaformat-intellij-idea-plugin[IntelliJ IDEA plugin].
* Select "`IntelliJ IDEA`" -> "`Preferences`".
* Select "`Plugins`".
* Select the wheel and "`Install Plugin from Disk...`".
* Select the jar file you've downloaded.



==== Import additional code style
The formatter does not cover all rules (such as order of imports) and an additional file needs to be added.

* Select "`IntelliJ IDEA`" -> "`Preferences`".
* Select "`Editor`" -> "`Code Style`".
* Select the wheel and "`Import Scheme`" -> "`IntelliJ IDEA code style XML`".
* Select `idea/codeStyleConfig.xml` from this repository.



=== Importing into Other IDEs
Gradle is well supported by most Java IDEs. Refer to your vendor documentation.



== Cloning the git repository on Windows
Some files in the git repository may exceed the Windows maximum file path (260 characters), depending on where you clone the repository.
If you get `Filename too long` errors, set the `core.longPaths=true` git option:

```
git clone -c core.longPaths=true https://github.com/spring-projects/spring-boot
```
