= Contributing to Spring Boot Spring Boot is released under the Apache 2.0 license. If you would like to contribute something, or simply want to hack on the code this document should help you get started. == 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 https://github.com/spring-projects/spring-boot-issues[sample project] that reproduces the problem. == 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. * Use the Spring Framework code format conventions. If you use Eclipse and you follow the '`Importing into eclipse`' instructions below you should get project specific formatting automatically. You can also import formatter settings using the `eclipse-code-formatter.xml` file from the `eclipse` folder. If using IntelliJ IDEA, you can use the https://plugins.jetbrains.com/plugin/6546[Eclipse Code Formatter Plugin] to import the same file. * Make sure all new `.java` files to have a simple 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], if you are fixing an existing issue please add `Fixes gh-XXXX` at the end of the commit message (where `XXXX` is the issue number). == Working with the code If you don't have an IDE preference we would recommend that you use https://www.springsource.com/developer/sts[Spring Tools Suite] or https://eclipse.org[Eclipse] when working with the code. We use the https://eclipse.org/m2e/[M2Eclipse] eclipse plugin for maven support. Other IDEs and tools should also work without issue. === Building from source To build the source you will need to install https://maven.apache.org/run-maven/index.html[Apache Maven] v3.2.3 or above and JDK 1.8. ==== Default build The project can be built from the root directory using the standard maven command: [indent=0] ---- $ ./mvnw clean install ---- NOTE: You may need to increase the amount of memory available to Maven by setting a `MAVEN_OPTS` environment variable with the value `-Xmx512m` If you are rebuilding often, you might also want to skip the tests until you are ready to submit a pull request: [indent=0] ---- $ ./mvnw clean install -DskipTests ---- ==== Full Build Multi-module Maven builds cannot directly include maven plugins that are part of the reactor unless they have previously been built. Unfortunately this restriction causes some compilations for Spring Boot as we include a maven plugin and use it within the samples. The standard build works around this restriction by launching the samples via the `maven-invoker-plugin` so that they are not part of the reactor. This works fine most of the time, however, sometimes it's useful to run a build that includes all modules (for example when using `maven-versions-plugin`. We use the full build on our CI servers and during the release process. Running a full build is a two phase process. 1) Prepare the build Preparing the build will compile and install the `spring-boot-maven-plugin` so that it can be referenced during the full build. It also generates a `settings.xml` file that enables a `snapshot`, `milestone` or `release` profiles based on the version being build. To prepare the build, from the root directory use: [indent=0] ---- $ ./mvnw -P snapshot,prepare install -DskipTests ---- NOTE: You may notice that preparing the build also changes the `spring-boot-starter-parent` POM. This is required for our release process to work correctly. 2) Run the full build Once the build has been prepared, you can run a full build using the following commands: [indent=0] ---- $ ./mvnw -s ./settings.xml -f spring-boot-full-build -P full clean install ---- NOTE: As for the standard build, you may need to increase the amount of memory available to Maven by setting a `MAVEN_OPTS` environment variable with the value `-Xmx512m`. We generate more artifacts when running the full build (such as Javadoc jars), so you may find the process a little slower than the standard build. === Importing into eclipse You can import the Spring Boot code into any Eclipse Mars based distribution. The easiest way to setup a new environment is to use the Eclipse Installer with the provided `.setup` file. ==== 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 Eclipse Installer from https://www.eclipse.org/downloads/[eclipse.org/downloads/]. * 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 and click "`next`". * For the "`Project`" click on "`+`" to add a new setup file. Select "`Github Projects`" and browser for `/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. ==== Manual installation with m2eclipse If you prefer to install Eclipse yourself we recommend that you use the https://eclipse.org/m2e/[M2Eclipse] eclipse plugin. If you don't already have m2eclipse installed it is available from the "Eclipse marketplace". Spring Boot includes project specific source formatting settings, in order to have these work with m2eclipse, we provide additional Eclipse plugins that you can install: ===== Install the m2eclipse-maveneclipse plugin * Select "`Help`" -> "`Install New Software`". * Add `https://dl.bintray.com/philwebb/m2eclipse-maveneclipse` as a site. * Install "Maven Integration for the maven-eclipse-plugin" ===== Install the Spring Formatter plugin * Select "`Help`" -> "`Install New Software`". * Add `https://dl.bintray.com/philwebb/spring-eclipse-code-formatter/` as a site. * Install "Spring Code Formatter" NOTE: These plugins are 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 `import existing maven projects` from the `file` menu to import the code. You will need to import the root `spring-boot` pom and the `spring-boot-samples` pom separately. ==== Importing into eclipse without m2eclipse If you prefer not to use m2eclipse you can generate eclipse project metadata using the following command: [indent=0] ---- $ ./mvnw eclipse:eclipse ---- The generated eclipse projects can be imported by selecting `import existing projects` from the `file` menu. === Importing into other IDEs Maven is well supported by most Java IDEs. Refer to your vendor documentation. == Integration tests The sample applications are used as integration tests during the build (when you `mvn install`). Due to the fact that they make use of the `spring-boot-maven-plugin` they cannot be called directly, and so instead are launched via the `maven-invoker-plugin`. If you encounter build failures running the integration tests, check the `build.log` file in the appropriate sample directory.