IntelliJ is popular and widely used by Beam developers, particularly for Java. If you're choosing a Java IDE, IntelliJ is a good choice.
These are best-effort community-contributed tips, and are not guaranteed to work with any particular IntelliJ setup.

Note: this documentation is currently under maintenance. You can help out as well! See: Unable to render Jira issues macro, execution error.

How to: Set up IntelliJ from scratch

TODO: Improve this documentation Unable to render Jira issues macro, execution error.

Create a working Gradle module

(as of IntelliJ 2018.1.6)

Create an empty IntelliJ project outside of the Beam source tree.
Under File > Project Structure > Project, select a Project SDK.
Under File > Project Structure > Modules, click the + sign to add a module and select “Import Module”.
1. Select the directory containing the Beam source tree.
2. Tick the “Import module from external model” button and select Gradle from the list.
3. Tick the following boxes.
  - Create separate module per source set
  - Use default gradle wrapper
Delegate build actions to Gradle by going to FIle > Settings/Preferences > Build, Execution, Deployment > Build Tools > Gradle > Runner and checking “Delegate IDE build/run actions to gradle”.

This should result in a working Gradle project. Build the project by executing the “build” task in the root Gradle module.

Checkstyle

IntelliJ supports checkstyle within the IDE using the Checkstyle-IDEA plugin.

Note: Older versions of IntelliJ may not support the Checkstyle file used by Beam.

Install the “Checkstyle-IDEA” plugin from the IntelliJ plugin repository
Configure the plugin by going to Settings -> Other Settings -> Checkstyle
Set Checkstyle version to the same as in /build_rules.gradle (e.g. 8.7)
Set the “Scan Scope” to “Only Java sources (including tests)”
In the “Configuration File” pane, add a new configuration using the plus icon:
1. Set the “Description” to “Beam”
2. Select “Use a local Checkstyle file”, and point it to sdks/java/build-tools/src/main/resources/beam/checkstyle.xml within your repository
3. Check the box for “Store relative to project location”, and click “Next”
4. Configure the checkstyle.suppressions.file property value to suppressions.xml, and click “Next”, then “Finish”
Select “Beam” as the only active configuration file, and click “Apply” and “OK”
Checkstyle will now give warnings in the editor for any Checkstyle violations

You can also scan an entire module by opening the Checkstyle tools window and clicking the “Check Module” button. The scan should report no errors.

Note: Selecting “Check Project” may report some errors from the archetype modules as they are not configured for Checkstyle validation.

Code Style

Uniform formatting for Java and Groovy code is automated by the build through the Spotless Gradle plugin. Instead of relying on the IDE, now you can run ./gradlew spotlessApply to reformat changes prior to commit.

If you want to autoformat in the same way while you are developing, use the Google Java Format plugin.

Code Insight Feature Problems

IntelliJ can't load large files (stack overflow post):

In IntelliJ 2016 and higher: go to Help → Edit Custom Properties → Paste the following inside the properties file:

#---------------------------------------------------------------------
# Maximum file size (kilobytes) IDE should provide code assistance for.
# The larger file is the slower its editor works and higher overall system memory requirements are
# if code assistance is enabled. Remove this property or set to very large number if you need
# code assistance for any files available regardless their size.
#---------------------------------------------------------------------
idea.max.intellisense.filesize=2500

IntelliJ can't recognize Python files (stack overflow post):
- Press CTRL + ALT + SHIT + S → Go to Project Settings → Facets → expand Python → click on child → Python Interpreter
- Project Settings → Modules → Expand module → Python → Dependencies → select Python module SDK

How to: Perform a full build